Iowa's magazines...

[bridav58]

I'm in a debate on another forum about Iowa's forward magazine's being penetrated .There have been statements that Iowa's forward magazines were too high in the ship. In that debate one gentleman is stating that a shell hitting right(of course with a flatter type of trajectory) at the waterline or just above it could bypass the class A part of the belt and penetrate the class B part of the belt quite easily. I've tried to point out that the outer voids are also full of oil & that would also offer quite a bit of protection if nothing else the outer STS plates could very well decap the shell . Anyways IMHO the shell would explode way before raching the Class b part of the belt.
What's your opinion?

[Warship NWS]

I would not that the armor on the Iowa had decappling plates and sloped armor. It would not have been an easy target to hit with unguided projectiles vs a ship moving and maneuvering at 30+ knots and that could shoot back at over 15nm with reasonable accuracy. Talking about it and doing it are two different things and damned few BBs ever blew up due to *direct* hits on magazines.. for that matter, no one can prove conclusively that it ever happened - not even the Hood nor the BCs at Jutland.

[john964]

I would not that the armor on the Iowa had decappling plates and sloped armor. It would not have been an easy target to hit with unguided projectiles vs a ship moving and maneuvering at 30+ knots and that could shoot back at over 15nm with reasonable accuracy. Talking about it and doing it are two different things and damned few BBs ever blew up due to *direct* hits on magazines.. for that matter, no one can prove conclusively that it ever happened - not even the Hood nor the BCs at Jutland.

IIRC the BC's at Jutland had there turret roofs hit which resulted in flashfires going down to the magazines through poorly designed ammo handling equipment.

[Warship NWS]

IIRC the BC's at Jutland had there turret roofs hit which resulted in flashfires going down to the magazines through poorly designed ammo handling equipment.

There are a few plausible threories for what happened to the BCs at Jutland but none of them suggest a direct hit on the magazines themselves. The point is simple.. hitting a VERY SMALL spot in big ocean with non-guided ordnance at exactly the right angle of impact, vs possibly several layers of armor plate, hoping that your AP cap stays intact through those armor plates, hoping that our fuzing works as expected (remember we are talking fractions of a second here), hoping that the splinters and VERY small explosive filler causes a chain reaction, etc.. the chances of detonating a BB magazine from a direct shell hit were VERY low for the vast majority typical naval gunnery engagements. The other point is simple, why argue over something that has yet to ever be proven in combat throughout all of naval history? Like I said.. its one thing to talk about the theory of such an occurance - and that is all that anyone can claim with any reasonable plausibility, its quite another to figure out the odds of it happening in reality. Unless some of those big bang theorists come up with some real numbers based on reasonable evidence.. they have little to nothing to suppor their case.

Thanks.

[bridav58]

It was stated that South Dakota was lucky that the hit was on the barbette instead of the aforementioned theory . My problem with the theory is that at the range ANY BB would be vulnerable even Bismarck with her belt and turtle deck or even Yamato & not just Iowa's 16"/50's but even a 14" gun could penetrate just about any armor belt at the range South Dakota was hit. Furthermore as the last fight of the Bismarck shows close range fighting means very flat trajectory fire so how can a shell hit in a way to hit just at or above the waterline then hit only the class B part of the armor?

[old_pop2000]

...There have been statements that Iowa's forward magazines were too high in the ship. In that debate one gentleman is stating that a shell hitting right(of course with a flatter type of trajectory) at the waterline or just above it could bypass the class A part of the belt and penetrate the class B part of the belt quite easily.

Has anyone asked that person to define "to high in the ship". The armor scheme on the Iowa's was essentially the same as the SD class except the armored box was 464 feet long as compared to 360 for the SD and the Iowa's had an increase in draft of over 5 feet. One problem was the narrowing of the hull both forward and aft near the turrets which did reduce the hull space between the side and the magazines.

The chances of flatter trajectory shot hitting below the waterline, and penetrating the class B armor then getting defected downward to strike the magazines which were situated between the two forward turrets and aft of the rear turret would be on the order of the fickle finger of fate syndrome. At some point in my design process, I have to prioritize my threats because of weight considerations. While it is within the realm of possibilities, it's statistical probability makes the consideration of a defense against it, as unnecessary. There were other threats of a higher priority that required the armor weight and configuration. I can, of course, build a ship with a defensive armor scheme to defend against almost any threat, but I could not build the engines necessary to drive it or a structure large enough to float.

[bridav58]

Well since the class A armor extends from the 2nd deck all the way down to the 3rd deck with the waterline being between those 2 decks(remember that Iowa had 5' of armored freeboard while the class A part of the belt was about 11' deep) ,the outer part of the STS splinter plating was about what 6' (if that much)outboard of the main belt??? So just how in the heck can you get a trajectory that hit that class B armor with out hitting water first???

[Ed Rotondaro]

It was stated that South Dakota was lucky that the hit was on the barbette instead of the aforementioned theory . My problem with the theory is that at the range ANY BB would be vulnerable even Bismarck with her belt and turtle deck or even Yamato & not just Iowa's 16"/50's but even a 14" gun could penetrate just about any armor belt at the range South Dakota was hit. Furthermore as the last fight of the Bismarck shows close range fighting means very flat trajectory fire so how can a shell hit in a way to hit just at or above the waterline then hit only the class B part of the armor?

Brian:

South Dakota was also lucky that the sole 14" shell that hit her was a bombardment type shell that had no chance of penetrating her belt, turret, barbette or any other well armored spot. There are photos of this hit and you can see that the barbette is barely scratched.

[Ed Rotondaro]

Has anyone asked that person to define "to high in the ship". The armor scheme on the Iowa's was essentially the same as the SD class except the armored box was 464 feet long as compared to 360 for the SD and the Iowa's had an increase in draft of over 5 feet. One problem was the narrowing of the hull both forward and aft near the turrets which did reduce the hull space between the side and the magazines.

The chances of flatter trajectory shot hitting below the waterline, and penetrating the class B armor then getting defected downward to strike the magazines which were situated between the two forward turrets and aft of the rear turret would be on the order of the fickle finger of fate syndrome. At some point in my design process, I have to prioritize my threats because of weight considerations. While it is within the realm of possibilities, it's statistical probability makes the consideration of a defense against it, as unnecessary. There were other threats of a higher priority that required the armor weight and configuration. I can, of course, build a ship with a defensive armor scheme to defend against almost any threat, but I could not build the engines necessary to drive it or a structure large enough to float.

Dennis:

I agree. Most likely a shot at close range with flat trajectory would hit the superstructure or the turret, not the belt. The British found that when Rodney and KGV closed wtih Bismarck and tried to hit her belt, they were totally ineffective. Admiral Tovey actually considered opening the range in hopes of getting some plunging hits on the deck. (Source Garzke and Dulin Axis Battleships)

[Ed Rotondaro]

Well since the class A armor extends from the 2nd deck all the way down to the 3rd deck with the waterline being between those 2 decks(remember that Iowa had 5' of armored freeboard while the class A part of the belt was about 11' deep) ,the outer part of the STS splinter plating was about what 6' (if that much)outboard of the main belt??? So just how in the heck can you get a trajectory that hit that class B armor with out hitting water first???

Brian:

What you are dealing with here are some folks who took some data about armor penetration from either Nathan Okun's writings or some on-line source and then combined it with some data on the trajectory of a particular gun at a given range to come up a theoretical hit that could penetrate the armor. The realities and practicalities of achieving these conditions are of course not addressed because the people in question have just enough knowledge to be dangerous. You should have read the nonsense article on Overrated Battleships that I found on a popular wargame company's website.

[old_pop2000]

I'm in a debate on another forum about Iowa's forward magazine's being penetrated .There have been statements that Iowa's forward magazines were too high in the ship. In that debate one gentleman is stating that a shell hitting right(of course with a flatter type of trajectory) at the waterline or just above it could bypass the class A part of the belt and penetrate the class B part of the belt quite easily. I've tried to point out that the outer voids are also full of oil & that would also offer quite a bit of protection if nothing else the outer STS plates could very well decap the shell . Anyways IMHO the shell would explode way before raching the Class b part of the belt.
What's your opinion?

You probably have this information, but if not, use these tables to fortify your case. As Okun says, there are no absolutes, only probabilities.

http://www.geocities.com/kop_mic/

[bridav58]

You probably have this information, but if not, use these tables to fortify your case. As Okun says, there are no absolutes, only probabilities.

http://www.geocities.com/kop_mic/

I'm not saying it can't happen what they're saying but looking at Iowa's or South Dakota's cross section it would take IMHO a shell coming in at close to 30 degrees or more???? Anyways a very steep angle.

[Mike Malanaphy]

There are a few plausible threories for what happened to the BCs at Jutland but none of them suggest a direct hit on the magazines themselves. The point is simple.. hitting a VERY SMALL spot in big ocean with non-guided ordnance at exactly the right angle of impact, vs possibly several layers of armor plate, hoping that your AP cap stays intact through those armor plates, hoping that our fuzing works as expected (remember we are talking fractions of a second here), hoping that the splinters and VERY small explosive filler causes a chain reaction, etc.. the chances of detonating a BB magazine from a direct shell hit were VERY low for the vast majority typical naval gunnery engagements. The other point is simple, why argue over something that has yet to ever be proven in combat throughout all of naval history? Like I said.. its one thing to talk about the theory of such an occurance - and that is all that anyone can claim with any reasonable plausibility, its quite another to figure out the odds of it happening in reality. Unless some of those big bang theorists come up with some real numbers based on reasonable evidence.. they have little to nothing to suppor their case.

Thanks.

Hi NWS,

I would agree, especially considering that neither the USS Boise or USS Savannah sucuumbed to magazine pentrations when hit. The USS Boise struck by an 8" Type 91 AP shell optimized for underwater trajectories and the Savannah hit by a guided bomb off Salerno. These ships were virtually floating magazines with fortunately stable powders.

[old_pop2000]

I'm not saying it can't happen what they're saying but looking at Iowa's or South Dakota's cross section it would take IMHO a shell coming in at close to 30 degrees or more???? Anyways a very steep angle.


You seem to be missing something here. The members on that forum that are arguing have couched their presentation in such a way, that you cannot win the argument. By preparing their arguments so that answers are either black or white, they eliminate probability. By doing so, you cannot defeat or win the contest. They are patently aware that what they are saying is a low probability shot. But, you cannot, with any real certainty say that it won't happen. Voila!! They win the argument and that is what they have always been attempting to do, win. These are not people interested in a stimulating, knowledgeable debate, just the debate. Until you bring in real, quantifiable data and prove the low probability of the shot, they are not going to listen. They aren't going to listen anyway. They are sitting at their desks, laughing at you. Give up the argument, not unless you have the time to understand and use Nathan Okun's formulas and tables to prepare a scholarly type reply, and then it will be lost on these people. You are wasting your time.

[Mike Malanaphy]

I'm not saying it can't happen what they're saying but looking at Iowa's or South Dakota's cross section it would take IMHO a shell coming in at close to 30 degrees or more???? Anyways a very steep angle.


Hi,

A shell coming at the angle would also face her inward sloping belt which would increase the angle of impact to over 40 degrees, not very favorable for penetration. Caps are designed to absorb lessen the shell's impact by spreading evenly over the shell body. That effect doesn't work at these angles of impact. The shell would be deflected or more likely break up. 16" high obliquity hits on the Jean Bart by the USS MAssachuesetts did not penetrate and the uneven angle of impact caused them to lose their bases fuzes and some of their explosive filler.

[old_pop2000]

Hi,

A shell coming at the angle would also face her inward sloping belt which would increase the angle of impact to over 40 degrees, not very favorable for penetration. Caps are designed to absorb lessen the shell's impact by spreading evenly over the shell body. That effect doesn't work at these angles of impact. The shell would be deflected or more likely break up. 16" high obliquity hits on the Jean Bart by the USS MAssachuesetts did not penetrate and the uneven angle of impact caused them to lose their bases fuzes and some of their explosive filler.


With an inclination of 19 degrees and an angle of trajectory of 30 degrees, we are looking at an angle near 50 degrees. Of course, the roll of the ship at any moment has to be account for, along with a host of other variables. We also have to include the type of shell, 16 inch or 18 inch, type of fuze, range, weather conditions, etc.

[Mike Malanaphy]

With an inclination of 19 degrees and an angle of trajectory of 30 degrees, we are looking at an angle near 50 degrees. Of course, the roll of the ship at any moment has to be account for, along with a host of other variable. We also have to include the type of shell, 16 inch or 18 inch, type of fuze, range, weather conditions, etc.

Hi Dennis,

Thanks I coudn't remember the slope of her belt. As has been said, your talking about a range of probablities in these types of discussions. It was very difficult for a large caliber AP shell to perform properly at more than 15 degrees of obliquity. The physical forces involved are quite spectacular.

[Ed Rotondaro]

Hi NWS,

I would agree, especially considering that neither the USS Boise or USS Savannah sucuumbed to magazine pentrations when hit. The USS Boise struck by an 8" Type 91 AP shell optimized for underwater trajectories and the Savannah hit by a guided bomb off Salerno. These ships were virtually floating magazines with fortunately stable powders.


Mike:

The other advantage was that while the USN's powder burned, it didn't flash like cordite, so the build up of gas was slower. And then of course the inrush of seawater extinguished the fires in both cases and prevented further build up of gas as well as preventing the shells from going off.

[Ed Rotondaro]

Hi Dennis,

Thanks I coudn't remember the slope of her belt. As has been said, your talking about a range of probablities in these types of discussions. It was very difficult for a large caliber AP shell to perform properly at more than 15 degrees of obliquity. The physical forces involved are quite spectacular.

Mike:

Frequently the effects of such a high level of obliquity is to put more stress on the shell as it tries to penetrate and literally squeeze the fuze out of the base like a champagne cork. That's why you see a fair amount of dud hits in actual recorded naval battles, the fuses were knocked out of action and the shell doesn't go off.

[Mike Malanaphy]

Mike:

Frequently the effects of such a high level of obliquity is to put more stress on the shell as it tries to penetrate and literally squeeze the fuze out of the base like a champagne cork. That's why you see a fair amount of dud hits in actual recorded naval battles, the fuses were knocked out of action and the shell doesn't go off.

HI Ed,

Wish I understood more abouit the physics. I can't remember if it was Hogg or Ogorkiewicz explaining about how caps worked. There was some ability of the cap top grip the surface and have the shell rotate towards the vertical to help with penetration. Perhaps Dennis can explain this to us. : )

[Ed Rotondaro]

HI Ed,

Wish I understood more abouit the physics. I can't remember if it was Hogg or Ogorkiewicz explaining about how caps worked. There was some ability of the cap top grip the surface and have the shell rotate towards the vertical to help with penetration. Perhaps Dennis can explain this to us. : )

Mike:

As Nathan Okun explains it on his guns and armor pages, a cap serves essentially two purposes:

1. It supports the shell's nose as it hits the armor plate and prevents it from shattering under the tremendous forces of impact. As Hogg points out, the ideal cap shape is not ballistically efficient, hence the thin windscreen cap to produce APCBC shells. There was usually a load of powdered dye in the void between to the thin windscreen and the piercing cap proper to assist in spotting. (Bear with me you probably already know this stuff).

2. The cap does allow as you say the shell to "bite" into the armor plate. Upon impact it generally became molten and helped lubricate the shell's penetration (too many adult references for one post sorry 'bout that;)

The effectiveness of capped shells is demonstrated by the armor designs intended to overcome them. De-capping decks and layers of side belt armor were incorporated to de-cap the shell and let it then explode against a thicker layer of armor and thereby trap the splinters from penetrating. Hogg mentions that there was an upper level to which steel shot finally would just bounce off of armor, hence the use of stronger materials such as tungsten carbide. This was more evident in anti-tank warfare where the gun velocities were much higher than in naval combat. Also the shell weights were much lower which aided in achieving that high velocity. Since the actual method of penetrating armor is by kinetic energy (KE= 1/2MxVsquared), you get more bang for the buck with a higher velocity. But since this causes steel shot to shatter, you can always take the other route and increase shell mass which is what was done for most naval artillery. The Russians also did this with their initial series of JS tanks, they used a moderate velocity 122mm gun with a very heavy shot to defeat the armor of Tiger tanks. Sorry for the long lecture.

[old_pop2000]

I'm in a debate on another forum about Iowa's forward magazine's being penetrated .There have been statements that Iowa's forward magazines were too high in the ship. In that debate one gentleman is stating that a shell hitting right(of course with a flatter type of trajectory) at the waterline or just above it could bypass the class A part of the belt and penetrate the class B part of the belt quite easily. I've tried to point out that the outer voids are also full of oil & that would also offer quite a bit of protection if nothing else the outer STS plates could very well decap the shell . Anyways IMHO the shell would explode way before raching the Class b part of the belt.
What's your opinion?


Ok, here are the original plans for the Battleship New Jersey. There is more detail here than you can use.

http://www.hnsa.org/doc/pdf/bbnjplans.pdf

[bridav58]

Ok, here are the original plans for the Battleship New Jersey. There is more detail here than you can use.

http://www.hnsa.org/doc/pdf/bbnjplans.pdf


It looks like to me that there's a bulkhead behind the holding bulkhead ,extending from A barbette back to B barbette . Pictures on pages 125 & 127 of Summerall's "Iowa Class Battleships" also seems to show bulkheads running from just A barbette to B barbette being constructed ,they seem to be about 1.5" STS . They are also below the 3rd. deck .

[Ed Rotondaro]

Ok, here are the original plans for the Battleship New Jersey. There is more detail here than you can use.

http://www.hnsa.org/doc/pdf/bbnjplans.pdf

Thanks Dennis, excellent details. Good enough for a scale modeler.

[old_pop2000]

Thanks Dennis, excellent details. Good enough for a scale modeler.


Thanks Ed, I hope they are useful in our future discussions.

[bridav58]

It looks like to me that there's a bulkhead behind the holding bulkhead ,extending from A barbette back to B barbette . Pictures on pages 125 & 127 of Summerall's "Iowa Class Battleships" also seems to show bulkheads running from just A barbette to B barbette being constructed ,they seem to be about 1.5" STS . They are also below the 3rd. deck .
It also appears to me that there was an extra inch of STS added to the 3rd deck over the magazines on top of the already existing .625" STS but maybe wrong.

[tony_glazebrook]

Mike:

As Nathan Okun explains it on his guns and armor pages, a cap serves essentially two purposes:

1. It supports the shell's nose as it hits the armor plate and prevents it from shattering under the tremendous forces of impact. As Hogg points out, the ideal cap shape is not ballistically efficient, hence the thin windscreen cap to produce APCBC shells. There was usually a load of powdered dye in the void between to the thin windscreen and the piercing cap proper to assist in spotting. (Bear with me you probably already know this stuff).

2. The cap does allow as you say the shell to "bite" into the armor plate. Upon impact it generally became molten and helped lubricate the shell's penetration (too many adult references for one post sorry 'bout that;)

The effectiveness of capped shells is demonstrated by the armor designs intended to overcome them. De-capping decks and layers of side belt armor were incorporated to de-cap the shell and let it then explode against a thicker layer of armor and thereby trap the splinters from penetrating. Hogg mentions that there was an upper level to which steel shot finally would just bounce off of armor, hence the use of stronger materials such as tungsten carbide. This was more evident in anti-tank warfare where the gun velocities were much higher than in naval combat. Also the shell weights were much lower which aided in achieving that high velocity. Since the actual method of penetrating armor is by kinetic energy (KE= 1/2MxVsquared), you get more bang for the buck with a higher velocity. But since this causes steel shot to shatter, you can always take the other route and increase shell mass which is what was done for most naval artillery. The Russians also did this with their initial series of JS tanks, they used a moderate velocity 122mm gun with a very heavy shot to defeat the armor of Tiger tanks. Sorry for the long lecture.

Ed - I'm intrigued a bit about the merits of de-capping. The Brits, who knew a thing or two about armour, went for the simple single thickness on deck and main belt in the KGV designs, after having pioneered more radical designs in the Nelson's, and of course being aware of the designs of the WW1 BBs (repeated in the Bismarck) of spaced belts. The Japs went for a single max thickness of main belt and deck armour also, save for some anti-splinter protection behind. Bit of similar story with the Richlieu's except that their anti splinter layer was thicker. Is it a cae of 6 of one, half a dozen of the other? It is known that all else being equal, a single thickness of x inches is balistically superior to 2 or more thicknesses totalling x inches, save for the decapping argument perhaps. Maybe the weight saved in not having a decapping layer allows for a thicker main layer, and net result is equal? There are of course many many variables. Maybe the de-capping effect works best within a more confined arc of impact? I seem to recall a study by Okun where he concluded that the Littorios, with some de-capping, were the best overall design theoretically (ie ignoring armour quallity)? What are your thoughts here?

Cheers mate

[Ed Rotondaro]

Ed - I'm intrigued a bit about the merits of de-capping. The Brits, who knew a thing or two about armour, went for the simple single thickness on deck and main belt in the KGV designs, after having pioneered more radical designs in the Nelson's, and of course being aware of the designs of the WW1 BBs (repeated in the Bismarck) of spaced belts. The Japs went for a single max thickness of main belt and deck armour also, save for some anti-splinter protection behind. Bit of similar story with the Richlieu's except that their anti splinter layer was thicker. Is it a cae of 6 of one, half a dozen of the other? It is known that all else being equal, a single thickness of x inches is balistically superior to 2 or more thicknesses totalling x inches, save for the decapping argument perhaps. Maybe the weight saved in not having a decapping layer allows for a thicker main layer, and net result is equal? There are of course many many variables. Maybe the de-capping effect works best within a more confined arc of impact? I seem to recall a study by Okun where he concluded that the Littorios, with some de-capping, were the best overall design theoretically (ie ignoring armour quallity)? What are your thoughts here?

Cheers mate

Tony:

I don't think any of these designs were ever tested properly in combat due to the paucity of battleship versus battleships actions. Indeed, they were more tested by aircraft versus battleship actions and no design proved invulnerable. Richard Worth and Nathan Okun have written essays on this topic over at the navweaps site and may probably have more insight than I could ever apply.

Cheers,

[William Miller]

The effectiveness of a 'decap plate' (or any outer armor layer) will vary based on a number of factors, but (in general) for a substantial plate such as that on the Iowa class versus the types of capped AP shells typically used by captial ships in the WW2 period the plate normally reduces net penetration by more than the raw thickness of the plate simply added to the belt if the shell is decapped. If the shell is not decapped then in most cases the net protection is less than the raw thickness of the plate added to the belt.

From my calculations the Iowa's decap plate would have better than a 50% chance to decap an 18.1" AP shell (i.e. the Yamato's primary round) at a typical striking angle at moderate range; if so it could reduce that shells net penetration by 4.6 to 6.1 inches against the belt depending upon the 3D impact angle and exact location of the hit. This is modeled in the NAW code of course...

[Warship NWS]

IMHO, part of what WM is trying to imply is that there is no certainty in the world of ballistics physics, only theory based on probabilities determined by the best possible calculations and available information that is meticulouly researched. There are a great number of variables involved with projectile vs armor physics along with the added dynamics of environmental combat conditions. This is one reason why I stated clearly at the start that any individual trying to claim, or imply, any level of certainty regarding the vulnerability of a very sophisticated and complex warship design of nearly 900' in lenth and 108' wide vs an unguided shell of no more then 1.5' in diameter hitting the right spot at the right moment in time and space during a typical naval engagement is showing utter arrogance tied with a varying degree of ignorance. This is of course hoping beyond hope everything after the impact works as expected which again adds a whole never dimension of complex variables to consider. If someone here, or there, cares to calculate the odds of such a specific result I personaly challenge them to give it their best shot, and I wish that individual a lot of luck.

[old_pop2000]

IMHO, part of what WM is trying to imply is that there is no certainty in the world of ballistics physics, only theory based on probabilities determined by the best possible calculations and available information that is meticulouly researched. There are a great number of variables involved with projectile vs armor physics along with the added dynamics of environmental combat conditions. This is one reason why I stated clearly at the start that any individual trying to claim, or imply, any level of certainty regarding the vulnerability of a very sophisticated and complex warship design of nearly 900' in lenth and 108' wide vs an unguided shell of no more then 1.5' in diameter hitting the right spot at the right moment in time and space during a typical naval engagement is showing utter arrogance tied with a varying degree of ignorance. This is of course hoping beyond hope everything after the impact works as expected which again adds a whole never dimension of complex variables to consider. If someone here, or there, cares to calculate the odds of such a specific result I personaly challenge them to give it their best shot, and I wish that individual a lot of luck.


Ah yes, the fickle finger of fate syndrome is alive and well. ;):D

[old_pop2000]

For those of you who might not have seen this updated article(5 years old) by Nathun Okun, here it is:

http://www.navweaps.com/index_tech/tech-085.htm

Note that according to the older article, the SD has a shell splinter plate which acts like a decapping plate and will decap any projectile up to 15.5 inches. The Iowas have the same plate, but it is 1.5 inches as opposed to 1.25 on the SD. As such, the Iowa armor scheme will decap any projectile over 18.6 inches.


Decapping an AP projectile greatly decreases their armor-penetration ability against face-hardened naval armor (unprotected projectile nose now shatters into pieces) at under 45° impact obliquity angle. Changes against softer homogeneous naval armors (decks, for example) are small--primarily due to the loss of the cap's weight. -Quoted from Nathan Okun's 1999 article.

Now, it would seem to me, that any shell hitting the Iowa's would be decapped and lose penetration before striking the main armor and as such, its chances of finding it way to the magazines is of a low probability. Low, not impossible. As for the comments about the mags being too high in the structure, that is nonsense. Qualify the statement "high" first.

Note to William: Thanks for your inputs during this busy time.

[tony_glazebrook]

The effectiveness of a 'decap plate' (or any outer armor layer) will vary based on a number of factors, but (in general) for a substantial plate such as that on the Iowa class versus the types of capped AP shells typically used by captial ships in the WW2 period the plate normally reduces net penetration by more than the raw thickness of the plate simply added to the belt if the shell is decapped. If the shell is not decapped then in most cases the net protection is less than the raw thickness of the plate added to the belt.

From my calculations the Iowa's decap plate would have better than a 50% chance to decap an 18.1" AP shell (i.e. the Yamato's primary round) at a typical striking angle at moderate range; if so it could reduce that shells net penetration by 4.6 to 6.1 inches against the belt depending upon the 3D impact angle and exact location of the hit. This is modeled in the NAW code of course...

Thanks William for the information, which is very interesting and helpful. I should have known of course that you would have studied this, and that it will be modelled in NAW! :cool:

[bridav58]

In Summerall's "Iowa Class Battleships" on page it shows in an actual picture not a "plan" or "line drawing " showing the shell mags being stored over the powder mags .

[old_pop2000]

In Summerall's "Iowa Class Battleships" on page it shows in an actual picture not a "plan" or "line drawing " showing the shell mags being stored over the powder mags .

Well that's fine, now you can go back, and win the argument. Wonderful:rolleyes:

[Ed Rotondaro]

In Summerall's "Iowa Class Battleships" on page it shows in an actual picture not a "plan" or "line drawing " showing the shell mags being stored over the powder mags .

Brian:

When I toured the USS Massachusetts, you could see that the powder was stored well below the shells, in fact at the very bottom deck of the ship.

[old_pop2000]

Brian:

When I toured the USS Massachusetts, you could see that the powder was stored well below the shells, in fact at the very bottom deck of the ship.

Yup, and if you examine the ship's plans, that is exactly what they tell you. They even allow you to determine the depth of those magazines and their width, and how far from the decapping plate those mags were located. They also give you the dimensions and type of steel for each plate and deck.

[Ed Rotondaro]

Yup, and if you examine the ship's plans, that is exactly what they tell you. They even allow you to determine the depth of those magazines and their width, and how far from the decapping plate those mags were located. They also give you the dimensions and type of steel for each plate and deck.

Dennis:

What was interesting was how little free space there was both in the turrets and in the shell handling rooms. It's easy to see why any damage to these areas would put them out of action easily.

[old_pop2000]

Dennis:

What was interesting was how little free space there was both in the turrets and in the shell handling rooms. It's easy to see why any damage to these areas would put them out of action easily.

I believe that Friedman makes the comment in his US Battleships that the SD class and the Iowa's were a little cramped because of the speed requirements. The Montana's were going to revert back to a more traditional design. They would have been slower, have more armor and probably have more room.

I may import the drawings into Autocad and do some real measuring. Might be fun.

[Ed Rotondaro]

I believe that Friedman makes the comment in his US Battleships that the SD class and the Iowa's were a little cramped because of the speed requirements. The Montana's were going to revert back to a more traditional design. They would have been slower, have more armor and probably have more room.

I may import the drawings into Autocad and do some real measuring. Might be fun.


Dennis:

The main reason for the SD class being cramped was the desire to put enough armor on them to resist 16" gunfire. The preceeding North Carolina class as designed was originally intended to carry 14" guns so her armor scheme reflected that. When the USN invoked the "elevator clause" in the naval treaties and installed 16" guns, there was no way to increase the armor and still stay at 35,000 tons displacement. So when the follow on class was designed, the ships were shortened to save weight for increased armor. While the SD class was a bit cramped, it was still better than most foreign designs for habitability. I had not heard that the Iowa class was cramped, more likely this was due to the increased size of the crew carried. The ships were designed to have a crew of 1,900. Due to increases in light AA, radar and communications, they shipped 2,800 crew. As you can imagine this would make even a big ship seem crowded.

[old_pop2000]

Dennis:

The main reason for the SD class being cramped was the desire to put enough armor on them to resist 16" gunfire. The preceeding North Carolina class as designed was originally intended to carry 14" guns so her armor scheme reflected that. When the USN invoked the "elevator clause" in the naval treaties and installed 16" guns, there was no way to increase the armor and still stay at 35,000 tons displacement. So when the follow on class was designed, the ships were shortened to save weight for increased armor. While the SD class was a bit cramped, it was still better than most foreign designs for habitability. I had not heard that the Iowa class was cramped, more likely this was due to the increased size of the crew carried. The ships were designed to have a crew of 1,900. Due to increases in light AA, radar and communications, they shipped 2,800 crew. As you can imagine this would make even a big ship seem crowded.

In the design of Iowa's, speed was the overriding consideration. They used the SD's armor scheme, but had to move the heaviest portion of the ship to the center and provide extra buoyancy. They also had to reduce wave creation as that dissipates energy into the wave and less to forward movement. The way they chose was to lengthen the ships increasing the length to beam in bow area but also increasing the draft. These two parameters- LtB and BtD are essential to gaining speed. To decrease weight, the reduced the stern. This gives the ship its unique shape. The bow has less buoyance and therefore is wetter than most battleships. One problem was the narrowing of the forward section put the barbettes closer to the side, thereby shortening the distance from the magazines to the sides. Unfortunately, this could not be helped. Both classes of BB's were considered to have unsatisfactory torpedo protection. The only way to alleviate this would be to introduce a torpedo blister, like the one installed on Enterprise later in the war. Unfortunately loss of speed is the result.

One can see that in the Montana's, they reduced the speed to gain protection and additional firepower. In other words, they reverted to traditional battleship design techniques.

[bridav58]

It seems that not only are Iowa's powder magazine undeneath the 3rd deck which is listed as 1" STS but appears much thicker in Summerall's book but the 1st Platform deck is also thickened to 1" STS over the powder magazines while it's only 5/16" the rest of it's length.

[Ed Rotondaro]

In the design of Iowa's, speed was the overriding consideration. They used the SD's armor scheme, but had to move the heaviest portion of the ship to the center and provide extra buoyancy. They also had to reduce wave creation as that dissipates energy into the wave and less to forward movement. The way they chose was to lengthen the ships increasing the length to beam in bow area but also increasing the draft. These two parameters- LtB and BtD are essential to gaining speed. To decrease weight, the reduced the stern. This gives the ship its unique shape. The bow has less buoyance and therefore is wetter than most battleships. One problem was the narrowing of the forward section put the barbettes closer to the side, thereby shortening the distance from the magazines to the sides. Unfortunately, this could not be helped. Both classes of BB's were considered to have unsatisfactory torpedo protection. The only way to alleviate this would be to introduce a torpedo blister, like the one installed on Enterprise later in the war. Unfortunately loss of speed is the result.

One can see that in the Montana's, they reduced the speed to gain protection and additional firepower. In other words, they reverted to traditional battleship design techniques.

Dennis:

Yes from what I've read the Iowa class made certain changes solely to gain that 33 knot top speed (which no one can verify that the ships actually achieved, at least before their modernization). One has to question the entire rationale for the 33 knot top speed. Wouldn't 30 knots have been sufficient? The shadow cast by the Scharnhorst and Bismarck classes seemed to really preoccupy the USN's design board. They felt they needed a ship that could catch these powerful vessels, yet the answer was right there all along, simply use airpower. I would be that you could have designed a 30 knot Iowa that could keep up with carriers and still have a better armor scheme than the eventual design had. The 28 knot Duke of York managed to run down the Scharnhorst (albeit with help from a lucky boiler hit and then torpedo attacks).

While the Montana class would have been a white elephant to say the least, I would have liked to have seen at least one built and in action if only to see if the design philosophy was sound.

[old_pop2000]

Dennis:

Yes from what I've read the Iowa class made certain changes solely to gain that 33 knot top speed (which no one can verify that the ships actually achieved, at least before their modernization). One has to question the entire rationale for the 33 knot top speed. Wouldn't 30 knots have been sufficient? The shadow cast by the Scharnhorst and Bismarck classes seemed to really preoccupy the USN's design board. They felt they needed a ship that could catch these powerful vessels, yet the answer was right there all along, simply use airpower. I would be that you could have designed a 30 knot Iowa that could keep up with carriers and still have a better armor scheme than the eventual design had. The 28 knot Duke of York managed to run down the Scharnhorst (albeit with help from a lucky boiler hit and then torpedo attacks).

While the Montana class would have been a white elephant to say the least, I would have liked to have seen at least one built and in action if only to see if the design philosophy was sound.

The Iowa's were never designed to fight in the battleline. They were the ultimate "cruiser killer". They were designed to escort the carriers and protect them against the Japanese cruisers and fast battleships like the Kongo's during the attrition raids that were expected. Now, as most of us should know, WPO was never a valid war plan and was superceded by WPL 46. In that, there would be no march across the mandates to engage the Japanese battlefleet, but a period for up to a year of just raids and defensive fighting to protect the Philippines and that southern area. But the carrier escort function was still a viable operational mission for the ships.

As to the Montana's, they were a response to the new 16 inch 50 cal. 2700 lb shell that could pierce the Iowa's armor. Most ships are designed with protection against their own projectiles but the new shell came out after the Iowa's were already designed and in the building stage. The Montana's were designed with armor protection to counter those shells. Another factor might be that it was found during actual operational missions that with war loading, most carriers did not attain the 33 knots, most kept their speeds around 28 or 29 knots. Only the Lexingtons could consistently attain 33 knots or higher. So, why build an escort to attain a speed that was not frequently used. Ships are compromises as with any weapon system. To add the armor, added weight. To compensate, then the draught had to be increased and that would cause porting problems commensurate with deep draught ships. The added weight mean that to maintain the speed with would have had to increase the propulsions systems by adding additional boilers to gain the 250000 SHP necessary to drive the Montana's at the Iowa's speed. So, the easiest decision was to let the speed drop to 27 knots. If they maintained the 27 knot speed and the 880 foot length, they could mount a fourth turret and still keep the engineering plant at the same output. They could also increase the armor protection. This was a design philosophy compatible with the Navy's traditional requirements emphasizing firepower and protection over speed. The Navy probably also wanted to increase the secondary and tertiary firepower to combat Japanese destroyers which had become menacing in the initial stages of the war.

I may spend some time using Springsharp taking the Iowa report, then changing the variables one at a time to reflect the changes made on the Montana's and see how the planning and development progressed. Might be a fun exercise.

[Ed Rotondaro]

I may spend some time using Springsharp taking the Iowa report, then changing the variables one at a time to reflect the changes made on the Montana's and see how the planning and development progressed. Might be a fun exercise.

Dennis:

Sounds like fun. Let us know what you turn up.

[old_pop2000]

Dennis:

Sounds like fun. Let us know what you turn up.

Certainly will, however, I have an exercise and fitness class this afternoon, I also have a cooking class tomorrow evening, so I might be busy unless I get thrown out of the latter. :D

[Mike Malanaphy]

Dennis:

Yes from what I've read the Iowa class made certain changes solely to gain that 33 knot top speed (which no one can verify that the ships actually achieved, at least before their modernization). One has to question the entire rationale for the 33 knot top speed. Wouldn't 30 knots have been sufficient? The shadow cast by the Scharnhorst and Bismarck classes seemed to really preoccupy the USN's design board. They felt they needed a ship that could catch these powerful vessels, yet the answer was right there all along, simply use airpower. I would be that you could have designed a 30 knot Iowa that could keep up with carriers and still have a better armor scheme than the eventual design had. The 28 knot Duke of York managed to run down the Scharnhorst (albeit with help from a lucky boiler hit and then torpedo attacks).

While the Montana class would have been a white elephant to say the least, I would have liked to have seen at least one built and in action if only to see if the design philosophy was sound.

Hi Ed,

Speed was seen as a critical design factor in the Iowas primarily so they could do independent operations and deal with Japanese heavy cruisers. You raise a good point about design speed. In Brown's books about RN design, they had a designed speed, but also looked at speed with the ship not having been docked for 6 months. An important consideration for them as a large number of cruisers served on foreign station and when they may become involved in combat.

This gap between designed and actual speed was most apparent with the Italians who ran ships on unrealistically light loads for higher speeds. Those higher speeds were not available in service and had lead to a compromise of their combat qualities.

[Ed Rotondaro]

Certainly will, however, I have an exercise and fitness class this afternoon, I also have a cooking class tomorrow evening, so I might be busy unless I get thrown out of the latter. :D

Dennis:

Sounds like you're keeping busy. What does your new latin sign off translate to?

[Ed Rotondaro]

Hi Ed,

Speed was seen as a critical design factor in the Iowas primarily so they could do independent operations and deal with Japanese heavy cruisers. You raise a good point about design speed. In Brown's books about RN design, they had a designed speed, but also looked at speed with the ship not having been docked for 6 months. An important consideration for them as a large number of cruisers served on foreign station and when they may become involved in combat.

This gap between designed and actual speed was most apparent with the Italians who ran ships on unrealistically light loads for higher speeds. Those higher speeds were not available in service and had lead to a compromise of their combat qualities.

Mike:

It's interesting to note that running at high speed also depletes fuel at a much faster rate. I doubt any capital ship would have run a full speed for any longer than it would take to either escape from action or to bring an enemy ship to battle. When USS Washington operated with the RN in the spring of 1942, Admiral Tovey in the KGV watched in dismay as his ship needed to fuel far more often than the the US BB. Malcolm Muir refers to the Iowa class in his book as "designed for eccentric operations" meaning possibly commerce raiding as well as hunting down other large commerce raiders. This was also some of the rationale behind the design of the Alaska class. The USN didn't have a ship that could catch the German commerce raiders and hoepfully defeat them (although I believe a pair of New Orleans class CAs could have defeated any of the "pocket battleships"). Hence we get ships like the Iowa and Alaska classes.

[Mike Malanaphy]

Mike:

It's interesting to note that running at high speed also depletes fuel at a much faster rate. I doubt any capital ship would have run a full speed for any longer than it would take to either escape from action or to bring an enemy ship to battle. When USS Washington operated with the RN in the spring of 1942, Admiral Tovey in the KGV watched in dismay as his ship needed to fuel far more often than the the US BB. Malcolm Muir refers to the Iowa class in his book as "designed for eccentric operations" meaning possibly commerce raiding as well as hunting down other large commerce raiders. This was also some of the rationale behind the design of the Alaska class. The USN didn't have a ship that could catch the German commerce raiders and hoepfully defeat them (although I believe a pair of New Orleans class CAs could have defeated any of the "pocket battleships"). Hence we get ships like the Iowa and Alaska classes.

Hi Ed,

The USN had always been range concious with the large distances in the Pacific and a lack of support bases as enjoyed by the RN. Both the RN and the French had single ships that could catch and defeat the panzerschiiffs, but the chances of them meeting in the vast reaches of the Atlantic were slim. The rise of effective naval and land based air power between 1936 and 1945 was astounding and unforseen by many of those planning strategies and the ships needed to carry them out. The Iowas and Alaskas were rendered obsolete while on the slipways for their primary missions, but were large enough and stable enough to accept large AA batteries to defend carriers.

In FSP, I have had good success with two Brooklyns against the Graf Spee. The two NOs should do pretty well also.

[Ed Rotondaro]

Hi Ed,

In FSP, I have had good success with two Brooklyns against the Graf Spee. The two NOs should do pretty well also.


Mike:

I'm not surprised by that since historically the two RN CLs were able to damage the Graf Spee and they were some of the smaller designs that only carried 6 6" guns each. Two Brooklyns would give you 30 6" guns, plus a speed advantage of 7 knots as well as two targets to deal with. The Cleveland class would be even more trouble since they had better fire control and better secondary batteries.

[old_pop2000]

Dennis:

Sounds like you're keeping busy. What does your new latin sign off translate to?

Easy is the descent to avernus- Aeneid by Virgil

Literally translated it means the descent into hell is easy. One of my favorites.

Yes, I am keeping busy but still have time to relax, watch the bird feeders from my window and enjoy the flowers and listen to my Handel, Bach and Mozart. We are planning another Alaska cruise in April, this time leaving from San Pedro so no flying. We will be sailing to Astoria, Oregon then to Juneau, Ketchekan, Skagway, Hubbard Glacier then back to Sitka then to Victoria, BC and back to San Pedro. It will be a two week cruise in a concierge suite hopefully, on the top deck of the boat. It will have a balcony so we can watch the fish and birds. Looking forward to it.

Future plans are to take a Scandanavian cruise then maybe a world cruise.

[Ed Rotondaro]

Easy is the descent to avernus- Aeneid by Virgil

Literally translated it means the descent into hell is easy. One of my favorites.

Yes, I am keeping busy but still have time to relax, watch the bird feeders from my window and enjoy the flowers and listen to my Handel, Bach and Mozart. We are planning another Alaska cruise in April, this time leaving from San Pedro so no flying. We will be sailing to Astoria, Oregon then to Juneau, Ketchekan, Skagway, Hubbard Glacier then back to Sitka then to Victoria, BC and back to San Pedro. It will be a two week cruise in a concierge suite hopefully, on the top deck of the boat. It will have a balcony so we can watch the fish and birds. Looking forward to it.

Future plans are to take a Scandanavian cruise then maybe a world cruise.

Dennis:

I recongnized Avernus but that's about it. Good quote. Sounds like your cruise will be fun.

[asnrobert]

I've taken on a PB with one Brooklyn and been able to win, but it can be dicey.

[Mike Malanaphy]

Easy is the descent to avernus- Aeneid by Virgil

Literally translated it means the descent into hell is easy. One of my favorites.

Yes, I am keeping busy but still have time to relax, watch the bird feeders from my window and enjoy the flowers and listen to my Handel, Bach and Mozart. We are planning another Alaska cruise in April, this time leaving from San Pedro so no flying. We will be sailing to Astoria, Oregon then to Juneau, Ketchekan, Skagway, Hubbard Glacier then back to Sitka then to Victoria, BC and back to San Pedro. It will be a two week cruise in a concierge suite hopefully, on the top deck of the boat. It will have a balcony so we can watch the fish and birds. Looking forward to it.

Future plans are to take a Scandanavian cruise then maybe a world cruise.

Hi Dennis,

Sounds like a good cruise. We're going on an Alaska cruise in two weeks leaving from Seattle. I hope the condensation from the dish washer doesn't fog up my porthole. : )

[old_pop2000]

Hi Dennis,

Sounds like a good cruise. We're going on an Alaska cruise in two weeks leaving from Seattle. I hope the condensation from the dish washer doesn't fog up my porthole. : )

Hey, have a good time. We had some fun weather when we crossed the Sea of Alaska heading to Anchorage, but it wasn't too bad. The coolest part is sailing up the fjord to Hubbard glacier, that has got be the greatest part.

Be careful with the glassware when you load it into the dishwasher, it breaks easily. If the condensation gets bad, bring some Rain-X, it works great. Heh heh!!

If you want to confuse or scare the locals, say something like " Come Olga, we go a-viking".:D

[Kyle Holgate]

Mike:

I'm not surprised by that since historically the two RN CLs were able to damage the Graf Spee and they were some of the smaller designs that only carried 6 6" guns each. Two Brooklyns would give you 30 6" guns, plus a speed advantage of 7 knots as well as two targets to deal with. The Cleveland class would be even more trouble since they had better fire control and better secondary batteries.

I find that the classifications of ships is largely meaningless other than maybe to tell you what size guns it has. We tend to lump ships from very small destroyer leader sorts all the way up to Brooklyns as light cruisers, but they can be quite different. I'm not so inclined to consider a 10,000 ton 6" gunned ship a "light cruiser". Ship toxonomy is not a science, it'd be interesting to try it if I had lots of time though! Figure out the species and genus and such of verous ships.

[john964]

Mike:

I'm not surprised by that since historically the two RN CLs were able to damage the Graf Spee and they were some of the smaller designs that only carried 6 6" guns each. Two Brooklyns would give you 30 6" guns, plus a speed advantage of 7 knots as well as two targets to deal with. The Cleveland class would be even more trouble since they had better fire control and better secondary batteries.
Ed, The 2 CL's at River Plate were Leander class with 8x6in guns the HMS Exeter was the one armed with only 6 guns. IIRC it was the Washington Treaty that defined what was and was not a CA or a CL. There were several classes of ships that didn't fit into either catagory very well like the Hawken class. The RN had several classes of CL's that only had 5 or 6, 6in guns in single mounts but all of these were WWI leftovers.

[asnrobert]

I find that the classifications of ships is largely meaningless other than maybe to tell you what size guns it has. We tend to lump ships from very small destroyer leader sorts all the way up to Brooklyns as light cruisers, but they can be quite different. I'm not so inclined to consider a 10,000 ton 6" gunned ship a "light cruiser". Ship toxonomy is not a science, it'd be interesting to try it if I had lots of time though! Figure out the species and genus and such of verous ships.

Also, a lot of times politics influences it. For instance, the Indiana class pre-dreadnoughts were classified as "ocean going coast defense battleships in order to get Congress to approve them. And Jackie Fisher's BCs Furious, Glorious and Courageous were classified as 'large light cruisers' to get past a Parliamentary ban on capital ships.

[Spook046]

Easy is the descent to avernus- Aeneid by Virgil

Literally translated it means the descent into hell is easy. One of my favorites.

Yes, I am keeping busy but still have time to relax, watch the bird feeders from my window and enjoy the flowers and listen to my Handel, Bach and Mozart. We are planning another Alaska cruise in April, this time leaving from San Pedro so no flying. We will be sailing to Astoria, Oregon then to Juneau, Ketchekan, Skagway, Hubbard Glacier then back to Sitka then to Victoria, BC and back to San Pedro. It will be a two week cruise in a concierge suite hopefully, on the top deck of the boat. It will have a balcony so we can watch the fish and birds. Looking forward to it.

Future plans are to take a Scandanavian cruise then maybe a world cruise.

If you have time while stopping in Astoria, feel free to seek out 620 Grand Ave. That was my home of 14 years ('68-'82).

[old_pop2000]

I find that the classifications of ships is largely meaningless other than maybe to tell you what size guns it has. We tend to lump ships from very small destroyer leader sorts all the way up to Brooklyns as light cruisers, but they can be quite different. I'm not so inclined to consider a 10,000 ton 6" gunned ship a "light cruiser". Ship toxonomy is not a science, it'd be interesting to try it if I had lots of time though! Figure out the species and genus and such of verous ships.

Classifications of ships are important only in the time period in which they occur. The term " cruiser" changed tasks and size over time. When comparing light cruisers, we have to ensure that we are using the term as it was conceived in the period. As you say, it is not an exacting science, but it isn't an art. It is simply a method of classification of tasks, not size.

[Warship NWS]

Classifications of ships are important only in the time period in which they occur.


Depends on your context.. IMHO, classifications are more to imply the mission of the class of warship then its weapons. Weapons are subject to opinion of effectiveness vs a variety of targets but the mission in and of itself did not change much in its general concept from the age of sail to even possibly modern day. It may mutate to a certain degree based on the circumstances of combat but the fundamental concept has remained for the most part the same in terms of classification by viable mission parameters.

Thanks.

[old_pop2000]

Depends on your context.. IMHO, classifications are more to imply the mission of the class of warship then its weapons. Weapons are subject to opinion of effectiveness vs a variety of targets but the mission in and of itself did not change much in its general concept from the age of sail to even possibly modern day. It may mutate to a certain degree based on the circumstances of combat but the fundamental concept has remained for the most part the same in terms of classification by viable mission parameters.

Thanks.

I believe my last statement covered that. Classification of ships is really only important in the time period it exist. It is a simple classification of tasks, not an established size. A cruiser had a defined mission in the fleet in the time period in question. It was built to a certain dimension, armament, armor and speed requirement as defined by that mission or missions. As the mission was redefined, then the requirements for a cruiser were modified to account for that new definition. As such, then the class might have been changed.

The mission or missions of the ship always dictated the building requirements for the ship. This has always been true in naval history. That does not preclude a ship from performing extra duties that it was never intended to perform, in many cases that is exactly what happened. All weapons classifications have been that way. You cannot become fixated on the terms, one must examine the missions to compare ships of a similar class.

[Warship NWS]

A very generalized context for warship classifications could be the following,

Battleships - the primary fighting warships intended for naval dominance prior to air power. Ironclads, ships of the line (1st to 4th rate), dreadnoughts, etc.. could all fall into this catagory.

Cruisers - naval gunfire support/flanking-maneuver/screening warships also intended for commerce patrol or raiding. Sailing frigates (5th-6th rate), scout/treaty cruisers, heavy/light cruisers, etc.. could fall into this catagory. Battlecruisers, a naval anomoly to some degree, fell somewhere between a cruiser and battleship depending on its intended mission.

Destroyers - small yet powerful ships designed for speed and high maneuverability, all purpose but local naval control warship due to limited crew/fuel endurance. Could also be used to effect enemy cohesion, raiding parties, merchant escorting, etc.. Sloops of war, torpedo boat destroyers, etc..

In general purpose the ships held the same missions throughout most of the gun-on-ship naval history even if they had different "names" for the classes.

Thanks.

[old_pop2000]

Cruisers - naval gunfire support/flanking-maneuver/screening warships also intended for commerce patrol or raiding. Sailing frigates (5th-6th rate), scout/treaty cruisers, heavy/light cruisers, etc.. could fall into this catagory

The term "cruiser" does not arise in navy's until the late nineteenth century and then it was a designation for a task, not a ship. They could be frigates or sloops of war and their mission was outside the main battle fleet. In the 1890's, I believe, we have the first designation of a ship designed for that role, to be so named "a cruiser". Again, as with other tasks and ships, they changed. The role of a 1950's cruiser was decidedly different from that of the cruiser of 1895, however, they still retained the designation of a cruiser. The time period and doctrine of that period, is the important aspect to be examined.

The term "ship of the line" always equated to the battleship, was not a type, but a task. Usually, in the 15th and 16th century a carrack performed that role. The name " ship of the line" does not enter naval history until the "the line of battle" tactic is developed in the late 17th century. This class or classes of ship, developed into the class we know as the battleship. In fact, the name is derived from the term "battery ship" a ship with all its guns concentrated in a central battery. Both ships were designed to gain sea control over the enemy, but that is a very generalized purpose. All naval ships were designed to support the navy, who purpose was to gain control of sea lanes of communication.

[Ed Rotondaro]

Ed, The 2 CL's at River Plate were Leander class with 8x6in guns the HMS Exeter was the one armed with only 6 guns. IIRC it was the Washington Treaty that defined what was and was not a CA or a CL. There were several classes of ships that didn't fit into either catagory very well like the Hawken class. The RN had several classes of CL's that only had 5 or 6, 6in guns in single mounts but all of these were WWI leftovers.


John:

Thanks, I stand corrected. I got them confused with the Arethusa class which had six 6" guns (but they were in double mounts and not WWI leftovers so there LOL!). Thanks for keeping me honest. Point being they only could only bring about the same firepower as one Brooklyn class CL.

[Ed Rotondaro]

If you have time while stopping in Astoria, feel free to seek out 620 Grand Ave. That was my home of 14 years ('68-'82).

Hi Spook:

Good to hear from you again sir. How's it going?

[Mike Malanaphy]

Hey, have a good time. We had some fun weather when we crossed the Sea of Alaska heading to Anchorage, but it wasn't too bad. The coolest part is sailing up the fjord to Hubbard glacier, that has got be the greatest part.

Be careful with the glassware when you load it into the dishwasher, it breaks easily. If the condensation gets bad, bring some Rain-X, it works great. Heh heh!!

If you want to confuse or scare the locals, say something like " Come Olga, we go a-viking".:D

Hi Dennis,

Exactly. I was amazed at how maneuverable the cruise ship was in that space. A grand spectalce...wished one of the ice walls had cracked off like on the Discovery Channel.
The fiord at Skagway is gorgeous too with teh tiny town at teh end of it. Only marred by teh cryuise shiup dock. We were in Skagway with two other ships, more like Times Square than the frontier..

[Mike Malanaphy]

Ed, The 2 CL's at River Plate were Leander class with 8x6in guns the HMS Exeter was the one armed with only 6 guns. IIRC it was the Washington Treaty that defined what was and was not a CA or a CL. There were several classes of ships that didn't fit into either catagory very well like the Hawken class. The RN had several classes of CL's that only had 5 or 6, 6in guns in single mounts but all of these were WWI leftovers.

Hi John,

The cruiser saga between wars is interesting. With the 10 year Battleship Holiday, the Wasghington Treaty sparked a mini arms race with cruisers. As you mentioned, the Washington treaty established A (Heavy) and B class cruisers (Light). A class wiith 7.9" or larger guns and B class with under 7.9". The British wanted the 7.5" armed Hawkins class to be excluded from the A class category so the limit was set at 7.9". With her Empire, the British were particularly concerned with cruisers for trade protection and working with the fleet. They wanted a total of 70 cruisers, but economics and tonnage restrictions prevented that. The Exeters and Arethusa's were cut down versions of four turret ships to provide more tonnage for numbers. It was thought based upon WW I exerience that they would not face major warships, but primarily merchant conversions. OOPs, but they were tough little ships that provided sterling service.

[Ed Rotondaro]

The term "cruiser" does not arise in navy's until the late nineteenth century and then it was a designation for a task, not a ship. They could be frigates or sloops of war and their mission was outside the main battle fleet. In the 1890's, I believe, we have the first designation of a ship designed for that role, to be so named "a cruiser". Again, as with other tasks and ships, they changed. The role of a 1950's cruiser was decidedly different from that of the cruiser of 1895, however, they still retained the designation of a cruiser. The time period and doctrine of that period, is the important aspect to be examined.

The term "ship of the line" always equated to the battleship, was not a type, but a task. Usually, in the 15th and 16th century a carrack performed that role. The name " ship of the line" does not enter naval history until the "the line of battle" tactic is developed in the late 17th century. This class or classes of ship, developed into the class we know as the battleship. In fact, the name is derived from the term "battery ship" a ship with all its guns concentrated in a central battery. Both ships were designed to gain sea control over the enemy, but that is a very generalized purpose. All naval ships were designed to support the navy, who purpose was to gain control of sea lanes of communication.

Dennis and Chris:

The term cruiser as has been stated defines it role more than its weapons. As Dennis states, cruisers were meant to operate independently from the fleet. They would show the flag in distant waters, they could suppress piracy, they could be spared from the main fleet unlike a ship of the line. We really don't see the term cruiser appearing until the advent of steam power and armor plate. Prior to that it is either frigate or perhaps sloop performing these duties. Even with the advent of the term cruiser, we see numerous types of ships classed as such: Armored cruisers, protected cruisers, second rate cruisers, third rate cruisers, scout cruisers. It is interesting to note that the light cruiser as a ship type proceeds and replaces just about all of the above cruisers and pretty much sets the tone for this type of ship's mission: Scouting, hunting down commerce raiders, screening, and acting as a flagship for destroyer flotillas. It wasn't until the London Naval Treaty that we even have the term "heavy cruiser" in the naval lexicon and that was merely to distinguish the weapons carried rather than the missions intended for the ship.

Destroyers are a little unusual in that they really were purpose built ships whose roles evolved over time. Prior to the torpedo, such ships really had no role in a fleet. In terms of size and tonnage, they more closely resemble a sloop. Originally termed torpedo boat destroyers, their name alone defines their initial function. A ship powerful enough and fast enough to counter the new torpedo boats that threatened the battleline. Once equipped with torpedoes, they replaced the torpedo boat and began to assume their new duties as scouts, screening ships and fast attack vessels. With the advent of the submarine, they assumed new duties as escort ships and ASW vessels. With the coming of aircraft, they became part of the AA screen of the fleet as well as long range pickets. They remain the premier surface warfare ship due to their versatility and affordability (although the new DDG-1000 may prove to costly to field in adequate numbers).

[old_pop2000]

Hi Dennis,

Exactly. I was amazed at how maneuverable the cruise ship was in that space. A grand spectalce...wished one of the ice walls had cracked off like on the Discovery Channel.
The fiord at Skagway is gorgeous too with teh tiny town at teh end of it. Only marred by teh cryuise shiup dock. We were in Skagway with two other ships, more like Times Square than the frontier..

Yes, it was interesting how they turned the fantail around. There was a boat near our ship when we were there and a big chunk did fall off. It was fascinating. I agree about the fjord at Skagway, I felt like a viking longship sailing up the fjords of Norway. There it was, a little town. We took the bus trip up the side of the hill to the vantage point and it really is beautiful. Terrible in winter, only 400 people actually live their permanently. Did you see the flower gardens on the walkway as you leave the boat dock? Maybe you were on the other boat dock. We were on the one nearest the right edge of the inlet. All we could see from our balcony was a pure rock face.

[john964]

John:

Thanks, I stand corrected. I got them confused with the Arethusa class which had six 6" guns (but they were in double mounts and not WWI leftovers so there LOL!). Thanks for keeping me honest. Point being they only could only bring about the same firepower as one Brooklyn class CL.If you want weak CL's try the Capt Romani class by the Italians IIRC about 3700tn with 8x5.3in mains Hell the Atlanta's have got more moxy than these oversized destroyers. Hell several DD's have almost the same firepower eg Porter and Tribal class.

[Mike Malanaphy]

Yes, it was interesting how they turned the fantail around. There was a boat near our ship when we were there and a big chunk did fall off. It was fascinating. I agree about the fjord at Skagway, I felt like a viking longship sailing up the fjords of Norway. There it was, a little town. We took the bus trip up the side of the hill to the vantage point and it really is beautiful. Terrible in winter, only 400 people actually live their permanently. Did you see the flower gardens on the walkway as you leave the boat dock? Maybe you were on the other boat dock. We were on the one nearest the right edge of the inlet. All we could see from our balcony was a pure rock face.

Hi Dennis,

We were there in 1996 and I only remeber one dock. Yikes, urban sprawl in Skagway.

[old_pop2000]

Hi Dennis,

We were there in 1996 and I only remeber one dock. Yikes, urban sprawl in Skagway.

When we were there, Holland America and Norwegian were docked at another pier about a half a mile from us. I don't know if that was the old or the new.

[bridav58]

Nathan Okun e-mailed me and gave his 2 cents worth on the issue though I think his opinion is worth far more then that !!! LOL !!!! He stated that the whole theory is flawed on a shell coming in at 22-23 degrees and missing the Class A part of the belt while hitting only the Class b part of the belt because the outer 1.5" STS even if they don't decap the shell will cause the shell to yaw upwards it then will either have to hit the .5" bulkhead behind the outer STS Shell which will cause it to yaw upward even more. As I take it the so-called "magic bullett through a window" just doesn't exist.
On another point I contacted Bill Tunney of the USS Alabama Memorial and he says that powder was loaded unto the ship down through the barbette to the handling room on the 2nd Platform deck then out to the adacent magazines ,then also up powder hoists to magazines on the 1st Platform Deck level so it does seem I was wrong in what I posted in that regards on that other forum but I don't think I'm going to tell them that!!! LOL !!! Actually I probably will confession is good for the soul !!! LOL !!!!
Also after reading Summerall's "Iowa Class Battleships" on page 75-76 he states the same thing as Bill Tunney says so if you like Iowa class BB's that is a very good book to get.

[old_pop2000]

Nathan Okun e-mailed me and gave his 2 cents worth on the issue though I think his opinion is worth far more then that !!! LOL !!!! He stated that the whole theory is flawed on a shell coming in at 22-23 degrees and missing the Class A part of the belt while hitting only the Class b part of the belt because the outer 1.5" STS even if they don't decap the shell will cause the shell to yaw upwards it then will either have to hit the .5" bulkhead behind the outer STS Shell which will cause it to yaw upward even more. As I take it the so-called "magic bullett through a window" just doesn't exist.


I don't know if I would say it doesn't exist. It exists as a mathematical probability. There is always a mathematical probability that the shell will not act as described, and penetrate. However, the probability is of such a low order as to be incalculable and as such, is improbable. However, as I am sure Mr. Okun would agree, not impossible. But, at least you have your answer.

[bridav58]

I don't know if I would say it doesn't exist. It exists as a mathematical probability. There is always a mathematical probability that the shell will not act as described, and penetrate. However, the probability is of such a low order as to be incalculable and as such, is improbable. However, as I am sure Mr. Okun would agree, not impossible. But, at least you have your answer.


Well I used a poor choice of words maybe in saying it didn't exist rather it's just not as easy as those other posters are making it sound. It doesn't exist ,as I would say, as a severe weakness or even a weakness per se in a design rather then as they put it like Iowa would be in the same position as HMS Hood when she blew up. However let's face how many times down through history how designers have designed things because of certain fears and those fears never pan out & the thing that could go wrong always seem to!!! LOL !!!! It's heavily disputed on wether it happened or not but look at Scharnhorst's boiler hump what was the chance a shell from Duke of York would hit that tiny target? That is true with all ships and navies though.

[Spook046]

Hi Spook:

Good to hear from you again sir. How's it going?

Trying to leverage out from my lurker status (it's been pretty hectic the last couple of months), with mixed results, but thanks for checking, fellow Ed. :)

[Mike Malanaphy]

If you want weak CL's try the Capt Romani class by the Italians IIRC about 3700tn with 8x5.3in mains Hell the Atlanta's have got more moxy than these oversized destroyers. Hell several DD's have almost the same firepower eg Porter and Tribal class.

Hi John,

They are interesting ships. Designed in 1937 as "Ocean Scouts", theyy were follow ons to the earlier light cruisers and designed to counter the French super destroyers. They were a new design, lighter and more compact the Condottieri classes. They traded protection for 8 DP 5.3" guns. The planned 65 mm AA guns were too long in gestation so they settled for the standard 37mm gun. They were designed for a speed of 41 knots which all met on their trials. Unlike other Italian ships, they were able to maintain this speed in combat condiitons. The captain of the Scipio Africano wrote effusively of the ship's fighting qualities after a skirmish with four British MTBs in the Straits of Messina on July 17, 1943. TYhe ship exceeding 40 knots in that encounter. The Italians claimed two sunk and another set on fire while the British admitted to the loss of one. With their speed, low silhouette, and DP armament, thye would be a good match against any destroyer save an American Fletcher, Sumner or Gearing which would get the nod for their better fire control, but might not be able to catch tehm.

12 ships were planned, but only three entered service before the Armistice.

Source: "Capitani Romani" parts 1 and 2, Warship Volume II

[bridav58]

He seems to be saying Yamato's armor is far superior to British armor.

http://members.aol.com/ghe101/ijn_yamato_vs_uss_iowa.htm

[Warship NWS]

He seems to be saying Yamato's armor is far superior to British armor.

http://members.aol.com/ghe101/ijn_yamato_vs_uss_iowa.htm

My personal opinion.. I have never seen any evidence to support most of his claims, and I think his final conclusions are inconclusive at best, severely faulty at worst. The simple statement of "The Iowa was not meant to be a brawler".. IMHO, is utterly bogus. His information about the radars is either pulled out of context, not evaluated correctly, or completely incorrect. He also left out the fact that the IJN had virtually no practical combat experience with their Mk2Mod SS/FCR (which was roughly comparable to our early Mk3 FCR which was replaced by the improved Mk8 and then Mk13). In anything but the best visibility conditions the Yamato would have been at a disadvantage, especially in terms of long range gunnery accuracy. The metalurgy of our shells was also marginally superior to their own whereas the 2700lb 16"/50 AP shell was roughly equal in terms of penetration vs the 18"/3000lb+ shell. IZ would also means diddly squat in terms of SS protection.. which would be nothing vs a heavy calibre shell. The probabilities of a ship losing its FC systems will be greater if it is his more often then it hits back -- simple measure of gunnery statistics and was also proven in various naval engagements. This is not even getting into the fact that the Iowas guns were better stabilized and had a marginally higher rate of fire - which could be sustained more consistently with accurate gunfire, spotting fire would not be needed as often. In the end run.. I think his article is biased and very inconclusive and leaves out a lot of tactical and technological considerations.

Thanks.

[old_pop2000]

He seems to be saying Yamato's armor is far superior to British armor.

http://members.aol.com/ghe101/ijn_yamato_vs_uss_iowa.htm

What are Strafford Morss credentials? He is a preservation engineer with Battleship Cove. He is a retire Navy Commander with a BS in Architectual Engineering. As a preservation engineer, does this qualify him as an expert on the subject of the Yamato and Iowa? Note also that the Warship International article referred to is in the No. 2 issue of 1986. That issue is no longer available. Hmmm!!

[Ed Rotondaro]

My personal opinion.. I have never seen any evidence to support most of his claims, and I think his final conclusions are inconclusive at best, severely faulty at worst. The simple statement of "The Iowa was not meant to be a brawler".. IMHO, is utterly bogus. His information about the radars is either pulled out of context, not evaluated correctly, or completely incorrect. He also left out the fact that the IJN had virtually no practical combat experience with their Mk2Mod SS/FCR (which was roughly comparable to our early Mk3 FCR which was replaced by the improved Mk8 and then Mk13). In anything but the best visibility conditions the Yamato would have been at a disadvantage, especially in terms of long range gunnery accuracy. The metalurgy of our shells was also marginally superior to their own whereas the 2700lb 16"/50 AP shell was roughly equal in terms of penetration vs the 18"/3000lb+ shell. IZ would also means diddly squat in terms of SS protection.. which would be nothing vs a heavy calibre shell. The probabilities of a ship losing its FC systems will be greater if it is his more often then it hits back -- simple measure of gunnery statistics and was also proven in various naval engagements. This is not even getting into the fact that the Iowas guns were better stabilized and had a marginally higher rate of fire - which could be sustained more consistently with accurate gunfire, spotting fire would not be needed as often. In the end run.. I think his article is biased and very inconclusive and leaves out a lot of tactical and technological considerations.

Thanks.

Chris et al:

Regarding Japanese battleships and Yamato in particular, I recently acquired an Osprey book entitled "Imperial Japanese Navy Battleships" by Cdmr. Mark Stille who is a frequent naval writer and wargamer designer. He states rather flatly that Japanese gunnery was bad if not attrocious and attributes it to a doctrine emphasing long ranged plunging fire. Indeed Japan's actual performance at gunnery practice never came close to the 12% that they claimed they were capable of. And to add insult to injury, the fleet never performed maneuvers based on the type of combat they planned on fighting. In a daylight action against a comparable US force, the IJN would get waxed badly. Too many of these on-line experts are going from lousy sources.

[Mike Malanaphy]

He seems to be saying Yamato's armor is far superior to British armor.

http://members.aol.com/ghe101/ijn_yamato_vs_uss_iowa.htm

Hi,
Sure sounds like it. Garke and Dulin mention a past war test in their volume on "Axis Battleships". A 600mm face plate from one of Shanano's turrets was taken to a test range at Dahlgren. Two 16" Mk8, Mod 6 rounds were fired against it. The first failed to pentrate while the second, fired at a higher velocity, went through the plate undamaged. No velocity, range, or obliquity data was supplied. The USN concluded that Japanese Vickers Hardened was inferior to US Class A armor by about 10%. The Yamato had a designed immunity zone against her own guns of 20,000-30,000 meters.

He mentions one interesting point. The US had no real knowledge of the Yamato's protection or main gun preformance, so the US captain would have to choose his range based perhaps on his immune zone or a range where he feels confident he can hot better.

In their US volume, they note the Iowa's had an immune zone of 17,600-31,700 yards against the 16"/45 2240 lb shell, this shrank to 20,400-26,700 against the 16"/45 firing the 2700 lb AP shell. This would likely be narrower against the 18."/45 Japanese gun firing a 3219 lb AP shell.

In terms of radar for gunfire, they mention a ranging error of af 300 meters at a range of 25,00 meters, but a bearing error of 5%. So the Yamato had no ability for blind firing and required clear visibility to see what she was shooting at.

[old_pop2000]

..... Too many of these on-line experts are going from lousy sources.

This very reason is why I asked the question as to what his bone fide's were? He is a paint specialist who was the VP at INRO, the publishers of Warship International. This does not say that he hasn't studied naval architecture, which he has, and that he doesn't understand armor and ballistics, but it does say that this is not his primary field of study. Just because he does preservaton work on the USS Massachusetts, does not immediately make him an expert in the above mentioned fields. I believe that men like Okun, Jurens, the late D.K.Brown, the crew at Navweaps, possibly even Norman Friedman have more experience and knowledge. I would also point out that the majority of the plans and building information on the Yamato's went up in flames during the war, due to a bombs. The NavJapReport states this as a reason for the dearth of real information on the ships.

[old_pop2000]

I stated earlier that I was going to use Springsharp to examine the transformation of the Iowa design to the Montana. Unfortunately, I do not have an Iowa configuration, so it will have to be created and validated. I am going to get the recommended book and use its figures such as freeboard etc. to assist. Once that is completed, then I can use Friedman to update to Montana and see what Springsharp says.

Sorry for the delay, but I have constraints like not enough literature and facts. I have to have the freeboard at the forecastle, the center and the stern to make the hull proper.

[Ed Rotondaro]

This very reason is why I asked the question as to what his bone fide's were? He is a paint specialist who was the VP at INRO, the publishers of Warship International. This does not say that he hasn't studied naval architecture, which he has, and that he doesn't understand armor and ballistics, but it does say that this is not his primary field of study. Just because he does preservaton work on the USS Massachusetts, does not immediately make him an expert in the above mentioned fields. I believe that men like Okun, Jurens, the late D.K.Brown, the crew at Navweaps, possibly even Norman Friedman have more experience and knowledge. I would also point out that the majority of the plans and building information on the Yamato's went up in flames during the war, due to a bombs. The NavJapReport states this as a reason for the dearth of real information on the ships.

Dennis:

Paint specialist? That's too funny, but in his defense, he may have done as much research as we try to do. From what I understand, the Japanese burned tons of documents after they surrendered to prevent the US from understanding their strategic and tactical situation.

[Ed Rotondaro]

I stated earlier that I was going to use Springsharp to examine the transformation of the Iowa design to the Montana. Unfortunately, I do not have an Iowa configuration, so it will have to be created and validated. I am going to get the recommended book and use its figures such as freeboard etc. to assist. Once that is completed, then I can use Friedman to update to Montana and see what Springsharp says.

Sorry for the delay, but I have constraints like not enough literature and facts. I have to have the freeboard at the forecastle, the center and the stern to make the hull proper.


Dennis:

I have Summerall's book on the Iowa class as well Friedman's book and Garzke and Dulin's book. If there are any numbers needed, please contact me and I'll do my best to supply them to you.

[old_pop2000]

Dennis:

I have Summerall's book on the Iowa class as well Friedman's book and Garzke and Dulin's book. If there are any numbers needed, please contact me and I'll do my best to supply them to you.


I need the freeboard data, Ed. It will be a range from the bow to the end of the forecastle, from the end of the forcastle to the poop deck, from the poop deck to the stern. It will be in a range like 26 ft at the bow lowering to 21 feet to the end of the forecastle. Also, the percentages of the forecastle, midships and poop deck based on the 880 feet. It could be in percentages like 15 percent for the forecastle. I would really appreciate it. I am going to get an Iowa book, but I just purchased definitive P-38 book.

[Ed Rotondaro]

I need the freeboard data, Ed. It will be a range from the bow to the end of the forecastle, from the end of the forcastle to the poop deck, from the poop deck to the stern. It will be in a range like 26 ft at the bow lowering to 21 feet to the end of the forecastle. Also, the percentages of the forecastle, midships and poop deck based on the 880 feet. It could be in percentages like 15 percent for the forecastle. I would really appreciate it. I am going to get an Iowa book, but I just purchased definitive P-38 book.

Dennis:

This is for the Iowa, not the Montana correct?

[old_pop2000]

Dennis:

This is for the Iowa, not the Montana correct?

Yes, for the Iowa class battleships. In order to start the process, I have to create a configuration file for the Iowa's then the program will create the report. Then I can play with the specifications to create the Montana's. The program isn't perfect, but it is the best I have.

Thanks

[Ed Rotondaro]

Yes, for the Iowa class battleships. In order to start the process, I have to create a configuration file for the Iowa's then the program will create the report. Then I can play with the specifications to create the Montana's. The program isn't perfect, but it is the best I have.

Thanks

Dennis:

OK, I'll see what I can dig up. I may need to query you if I find data is confusing.

[Warship NWS]

IZ.. the most overrated concept in naval history IMHO.

This is where many naval enthusiasts take the doctinal development of armored warships out of context and completely forget about the rest of the dynamics of naval gunnery combat. IZ was a design concept intended to keep enemy shells from getting into the engineering and/or ammo bunkers of a warship, AKA "vitals". The misconception of this concept is that it only covered what was below the deck of a warship.. nothing above it. Nothing below the deck did damage to the enemy .. that was all above the deck. Shells and engineering spaces did not aid in the destruction of the enemy unless the guns and fire controls work as expected.

IZ also gives the impression that unless you penetrate the armor of a ship you cannot damage the ship.. that is far from the truth or actual historical records. Immunity.. you cannot give a shot to a ship that keeps out all bad things. Guns could be damaged by non-penetrating hits and the ablity to even aim the guns was not armored against most calibres of naval shells - except maybe local fire control but by WW1 this would have been extremely ineffective. Armor plates are also not immovable objects.. they can be damaged, cracked, spalled, splintered, etc.. and concussion effects can still be very damaging.

The above are the parts the naval authors do not always decribe as they are covering the concepts, not always the tactics, doctrines, damage effects from non-penetrating gun hits, and the parts of a ship that could be damaged that were outside of the armored citadel. Amateur readers will often take the IZ football and run with it thinking a ship is completely immune to all bad things in combat like some sort of sci-fi impenetrable shield - thus taking the entire concept out of context and not applying it to real world naval combat. IZ was a concept on paper that seldom proved itself as usefull in actual combat as was intended on paper, plus, IZ could not apply to all naval guns and ammo types - only the "known" weapons.

Thanks.

[Ed Rotondaro]

Yes, for the Iowa class battleships. In order to start the process, I have to create a configuration file for the Iowa's then the program will create the report. Then I can play with the specifications to create the Montana's. The program isn't perfect, but it is the best I have.

Thanks

Dennis:

Unfortuntately neither Garkze and Dulin or Summerall give the level of detail on ship dimensions that you require. I'll see what else I can find. Sorry sir.

[Mike Malanaphy]

Dennis:

Unfortuntately neither Garkze and Dulin or Summerall give the level of detail on ship dimensions that you require. I'll see what else I can find. Sorry sir.

Hi Ed,

Is it possible to get those measurements from the scale drawings if not in tabular data?

[old_pop2000]

Hi Ed,

Is it possible to get those measurements from the scale drawings if not in tabular data?

I am going to print one of the drawings out and do some measuring tomorrow. I thought of the same thing.

[Mike Malanaphy]

He seems to be saying Yamato's armor is far superior to British armor.

http://members.aol.com/ghe101/ijn_yamato_vs_uss_iowa.htm

HI Guys,

Took me a while to find it, but I remember a similar claim about British armor. In their volume on "Alled Battleships", Dulin and Garke state that the side armor of the KGVs provided 25% more protection for equivalent weight than US Class A armor. There is no reference for that conclusion, but quoted above is a description of the manufacturing process from "Vickers-A History". In that process the face hardening of the plate extended to about 30% of it's depth. There is no mention of that difference in Raven and Robert's book "British Battleships of World War II". In their comparision with foreign types, they conclude that KGV could be penetrated by most of her contemporaries before she could penetrate them. In the Lions, the converse would be true.

[Ed Rotondaro]

HI Guys,

Took me a while to find it, but I remember a similar claim about British armor. In their volume on "Alled Battleships", Dulin and Garke state that the side armor of the KGVs provided 25% more protection for equivalent weight than US Class A armor. There is no reference for that conclusion, but quoted above is a description of the manufacturing process from "Vickers-A History". In that process the face hardening of the plate extended to about 30% of it's depth. There is no mention of that difference in Raven and Robert's book "British Battleships of World War II". In their comparision with foreign types, they conclude that KGV could be penetrated by most of her contemporaries before she could penetrate them. In the Lions, the converse would be true.


Mike:

Yes the British face hardening process made their armor slightly superior to US grade A armor. Richard Worth of Navweaps described the process once on a post. The main reason the US didn't use the more expensive and time consuming process that the RN used was that they had found that their super heavy heat treated AP shells could defeat face hardened armor so it was not worth the bother and cost to manufacture.

[old_pop2000]

As I promised, I finally got a decent preliminary report created for the IOWA class BB's using the SD class configuration modified. Here it is:


USS Iowa, USA Battleship laid down 1939

Displacement:
51,989 t light; 54,836 t standard; 60,486 t normal; 65,006 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(903.21 ft / 887.00 ft) x 108.14 ft x (36.30 / 38.45 ft)
(275.30 m / 270.36 m) x 32.96 m x (11.06 / 11.72 m)

Armament:
9 - 16.00" / 406 mm 50.0 cal guns - 2,168.09lbs / 983.43kg shells, 142 per gun
Breech loading guns in turret on barbette mounts, 1939 Model
3 x Triple mounts on centreline ends, majority forward
3 raised mounts
16 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1939 Model
8 x Single mounts on side ends, evenly spread
8 raised mounts
80 - 1.57" / 40.0 mm 45.0 cal guns - 1.97lbs / 0.89kg shells, 150 per gun
Anti-air guns in deck mounts, 1939 Model
20 x Quad mounts on side ends, evenly spread
20 raised mounts
34 - 0.79" / 20.0 mm 45.0 cal guns - 0.24lbs / 0.11kg shells, 150 per gun
Anti-air guns in deck mounts, 1939 Model
52 x Single mounts on side ends, evenly spread
34 raised mounts - superfiring
8 - 0.50" / 12.7 mm 45.0 cal guns - 0.07lbs / 0.03kg shells, 150 per gun
Machine guns in deck mounts, 1939 Model
8 x Single mounts on side ends, evenly spread
8 raised mounts
Weight of broadside 20,688 lbs / 9,384 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.2" / 310 mm 379.63 ft / 115.71 m 15.09 ft / 4.60 m
Ends: Unarmoured
Main Belt covers 66 % of normal length
Main belt does not fully cover magazines and engineering spaces
Main Belt inclined 19.00 degrees (positive = in)

- Torpedo Bulkhead - Additional damage containing bulkheads:
4.00" / 102 mm 379.63 ft / 115.71 m 24.54 ft / 7.48 m
Beam between torpedo bulkheads 88.14 ft / 26.87 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 19.7" / 500 mm 9.50" / 241 mm 17.3" / 439 mm
2nd: 2.00" / 51 mm 2.00" / 51 mm 2.00" / 51 mm
3rd: 0.50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 5.58" / 142 mm

- Conning towers: Forward 17.50" / 445 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 218,133 shp / 162,727 Kw = 32.50 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 10,170 tons

Complement:
1,927 - 2,506

Cost:
£27.775 million / $111.099 million

Distribution of weights at normal displacement:
Armament: 3,841 tons, 6.4 %
- Guns: 3,841 tons, 6.4 %
Armour: 15,526 tons, 25.7 %
- Belts: 3,233 tons, 5.3 %
- Torpedo bulkhead: 1,379 tons, 2.3 %
- Armament: 4,617 tons, 7.6 %
- Armour Deck: 5,717 tons, 9.5 %
- Conning Tower: 581 tons, 1.0 %
Machinery: 5,902 tons, 9.8 %
Hull, fittings & equipment: 26,665 tons, 44.1 %
Fuel, ammunition & stores: 8,497 tons, 14.0 %
Miscellaneous weights: 54 tons, 0.1 %
- Hull below water: 54 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
79,606 lbs / 36,109 Kg = 38.9 x 16.0 " / 406 mm shells or 11.9 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 5.6 ft / 1.7 m
Roll period: 19.2 seconds
Steadiness - As gun platform (Average = 50 %): 44 %
- Recoil effect (Restricted arc if above 1.00): 0.76
Seaboat quality (Average = 1.00): 0.77

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.608 / 0.617
Length to Beam Ratio: 8.20 : 1
'Natural speed' for length: 34.12 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 51
Bow angle (Positive = bow angles forward): 17.00 degrees
Stern overhang: 4.40 ft / 1.34 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 21.00 %, 38.63 ft / 11.77 m, 21.70 ft / 6.61 m
- Forward deck: 29.00 %, 21.70 ft / 6.61 m, 20.77 ft / 6.33 m
- Aft deck: 28.00 %, 20.77 ft / 6.33 m, 20.77 ft / 6.33 m
- Quarter deck: 22.00 %, 20.77 ft / 6.33 m, 21.77 ft / 6.64 m
- Average freeboard: 22.63 ft / 6.90 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 79.5 %
- Above water (accommodation/working, high = better): 153.0 %
Waterplane Area: 73,677 Square feet or 6,845 Square metres
Displacement factor (Displacement / loading): 127 %
Structure weight / hull surface area: 276 lbs/sq ft or 1,348 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.20
- Longitudinal: 1.28
- Overall: 1.21
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather


I've highlighted the freeboard area which was derived from the drawing and a ruler at 1/16" to 1 Ft. scale. If anyone has the actual numbers, don't be shy.

From this, I am going to then change variables to get the Montanas. You have the books gents, Am I close?

Just one thing, I can't keep posting the full report, or the MIB will get me, so I may just post the differences.

[tony_glazebrook]

As I promised, I finally got a decent preliminary report created for the IOWA class BB's using the SD class configuration modified. Here it is:



I've highlighted the freeboard area which was derived from the drawing and a ruler at 1/16" to 1 Ft. scale. If anyone has the actual numbers, don't be shy.

From this, I am going to then change variables to get the Montanas. You have the books gents, Am I close?

Just one thing, I can't keep posting the full report, or the MIB will get me, so I may just post the differences.

Dennis - I've just come across this post and I haven't read all the background on this thread so I am not sure what the purpose is, but to point out one thing - my references say the full load of the Iowas were less than 60,000 english tons (somewhere between 57,200 and 57,600 I think).

Cheers

[William Miller]

Dennis,

The Iowa class had ten twin 5"/38 gun mounts during it's WW2 career, not eight.

[old_pop2000]

Dennis,

The Iowa class had ten twin 5"/38 gun mounts during it's WW2 career, not eight.

Ha Ha!! That was an easy one, and you are absolutely correct. Will correct. Thanks

[old_pop2000]

Update per William Miller's correction for number of 5 in. turrets


USS Iowa, USA Battleship laid down 1939
Displacement:
50,258 t light; 53,089 t standard; 58,644 t normal; 63,089 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(876.21 ft / 860.00 ft) x 108.14 ft x (36.30 / 38.48 ft)
(267.07 m / 262.13 m) x 32.96 m x (11.06 / 11.73 m)
Armament:
9 - 16.00" / 406 mm 50.0 cal guns - 2,168.09lbs / 983.43kg shells, 142 per gun
Breech loading guns in turret on barbette mounts, 1939 Model
3 x Triple mounts on centreline ends, majority forward
3 raised mounts
20 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1939 Model
10 x Single mounts on side ends, majority forward
8 raised mounts - superfiring
80 - 1.57" / 40.0 mm 45.0 cal guns - 1.96lbs / 0.89kg shells, 150 per gun
Anti-air guns in deck mounts, 1939 Model
20 x Quad mounts on side ends, evenly spread
20 raised mounts
34 - 0.79" / 20.0 mm 45.0 cal guns - 0.24lbs / 0.11kg shells, 150 per gun
Anti-air guns in deck mounts, 1939 Model
52 x Single mounts on side ends, evenly spread
34 raised mounts - superfiring
8 - 0.50" / 12.7 mm 45.0 cal guns - 0.07lbs / 0.03kg shells, 150 per gun
Machine guns in deck mounts, 1939 Model
8 x Single mounts on side ends, evenly spread
8 raised mounts
Weight of broadside 20,939 lbs / 9,498 kg
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.2" / 310 mm 379.63 ft / 115.71 m 15.09 ft / 4.60 m
Ends: Unarmoured
Main Belt covers 68 % of normal length
Main belt does not fully cover magazines and engineering spaces
Main Belt inclined 19.00 degrees (positive = in)

- Torpedo Bulkhead - Additional damage containing bulkheads:
4.00" / 102 mm 379.63 ft / 115.71 m 24.54 ft / 7.48 m
Beam between torpedo bulkheads 88.14 ft / 26.87 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 19.7" / 500 mm 9.50" / 241 mm 17.3" / 439 mm
2nd: 2.00" / 51 mm 2.00" / 51 mm 2.00" / 51 mm
3rd: 0.50" / 13 mm
- Armoured deck - multiple decks:
For and Aft decks: 5.58" / 142 mm

- Conning towers: Forward 17.50" / 445 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 203,640 shp / 151,915 Kw = 32.00 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 10,000 tons
Complement:
1,883 - 2,449
Cost:
£27.243 million / $108.970 million
Distribution of weights at normal displacement:
Armament: 3,914 tons, 6.7 %
- Guns: 3,914 tons, 6.7 %
Armour: 15,365 tons, 26.2 %
- Belts: 3,229 tons, 5.5 %
- Torpedo bulkhead: 1,379 tons, 2.4 %
- Armament: 4,645 tons, 7.9 %
- Armour Deck: 5,543 tons, 9.5 %
- Conning Tower: 569 tons, 1.0 %
Machinery: 5,510 tons, 9.4 %
Hull, fittings & equipment: 25,415 tons, 43.3 %
Fuel, ammunition & stores: 8,386 tons, 14.3 %
Miscellaneous weights: 54 tons, 0.1 %
- Hull below water: 54 tons
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
76,557 lbs / 34,726 Kg = 37.4 x 16.0 " / 406 mm shells or 11.6 torpedoes
Stability (Unstable if below 1.00): 0.99
Metacentric height 5.6 ft / 1.7 m
Roll period: 19.3 seconds
Steadiness - As gun platform (Average = 50 %): 44 %
- Recoil effect (Restricted arc if above 1.00): 0.78
Seaboat quality (Average = 1.00): 0.77
Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.608 / 0.617
Length to Beam Ratio: 7.95 : 1
'Natural speed' for length: 33.68 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 51
Bow angle (Positive = bow angles forward): 17.00 degrees
Stern overhang: 4.40 ft / 1.34 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 21.00 %, 38.63 ft / 11.77 m, 21.70 ft / 6.61 m
- Forward deck: 29.00 %, 21.70 ft / 6.61 m, 20.77 ft / 6.33 m
- Aft deck: 28.00 %, 20.77 ft / 6.33 m, 20.77 ft / 6.33 m
- Quarter deck: 22.00 %, 20.77 ft / 6.33 m, 21.77 ft / 6.64 m
- Average freeboard: 22.63 ft / 6.90 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 79.7 %
- Above water (accommodation/working, high = better): 151.8 %
Waterplane Area: 71,434 Square feet or 6,636 Square metres
Displacement factor (Displacement / loading): 125 %
Structure weight / hull surface area: 273 lbs/sq ft or 1,331 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.17
- Longitudinal: 1.34
- Overall: 1.19
Caution: Poor stability - excessive risk of capsizing
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[old_pop2000]

Some interesting things I've discovered about these two ships.

The Iowa's were not good sea boats when fully loaded for war. They lost freeboard, which is essentially the distance from the WL to the main deck. The long thin bow was great for speed but meant that there was not a lot of buoyancy up forward and hence, she had the wet bow.

As to the Montana's, some sites on line claim they were 921 ft x 121 x 36 feet. However, Friedman claims that the final design was 891 x 115 x 36 and my configuration uses that figure. I also noted that when you use the 172,000 HP figure that was used in the design, you get a theoretical speed of around 29-30 knots. When you add the armor upgrade from 12.1 to 16.3 inches for the main belt and increase the turret armor, she tops out at over 70,000 tons under full load and the program tells you that they are good sea boats.

If we have some confidence in the program, the Montana's, due to the decrease in speed and increase in beam might have been much more stable gun platforms and better sea boats. I don't know what your books tell us, but that's why my work has shown. But I am not a naval architect. Not even a little bit.

[Ed Rotondaro]

Some interesting things I've discovered about these two ships.

The Iowa's were not good sea boats when fully loaded for war. They lost freeboard, which is essentially the distance from the WL to the main deck. The long thin bow was great for speed but meant that there was not a lot of buoyancy up forward and hence, she had the wet bow.

As to the Montana's, some sites on line claim they were 921 ft x 121 x 36 feet. However, Friedman claims that the final design was 891 x 115 x 36 and my configuration uses that figure. I also noted that when you use the 172,000 HP figure that was used in the design, you get a theoretical speed of around 29-30 knots. When you add the armor upgrade from 12.1 to 16.3 inches for the main belt and increase the turret armor, she tops out at over 70,000 tons under full load and the program tells you that they are good sea boats.

If we have some confidence in the program, the Montana's, due to the decrease in speed and increase in beam might have been much more stable gun platforms and better sea boats. I don't know what your books tell us, but that's why my work has shown. But I am not a naval architect. Not even a little bit.

Dennis:

The Iowa class never had their bows seriously tested so there is some valid concern as to how they would have stood up to battle damage, particularly a torpedo hit there.

[old_pop2000]

Dennis:

The Iowa class never had their bows seriously tested so there is some valid concern as to how they would have stood up to battle damage, particularly a torpedo hit there.

A lot of things about the Iowa's were never tested, Ed. We don't really know how good the seakeeping was until she went to the NA or a location other than the South and Central Pacific. Much of what what we have to go on, is theory and the SD class of BB's. We assume that if the SD's did well, so would the Iowa's. But their only adversary was a 20 year old battlecruiser upgraded to a battleship. Hard to know whether that was a fair representation of their abilities.

What battles in WWII can shed light on how post-WWI ship designers handled new problems in gunnery and aerial warfare? How can we judge the Iowa's?

[Kyle Holgate]

If Kirishima's 14" round had hit the barbette of SoDak directly...

Ship armor and protection is an interesting subject - it's interesting to look into the qualities of the armor itself once you've gotten the thicknesses figured out. Is it face hardened steel? Is it homogenous? Is the belt angled, and if so - how deep is it (top to bottom) as angle means it tends to cover less. Lots of things to consider.

[old_pop2000]

If Kirishima's 14" round had hit the barbette of SoDak directly...

Ship armor and protection is an interesting subject - it's interesting to look into the qualities of the armor itself once you've gotten the thicknesses figured out. Is it face hardened steel? Is it homogenous? Is the belt angled, and if so - how deep is it (top to bottom) as angle means it tends to cover less. Lots of things to consider.


Absolutely. There are many things to consider and that's why the best that can be said is the probability of an occurrance rather than an absolute. What would have happened had the 14 inch round hit the barbette directly? What's the probability of it penetrating? I certainly don't know. Here's what Nathan Okun says:


Thus, the impact was a potential disaster to the SOUTH DAKOTA if the shell had hit slightly higher and had its AP cap intact when it hit the plate. It might actually have penetrated in this case -- iffy, but barely possible -- and would most definitely have jammed the turret permanently until the ship went back an overhaul facility and had the damaged plate replaced and the internal barbette parts fixed. The decapping by the deck impact thus prevented all but rather minimal damage to the ship (the hit turret was still functional, if somewhat slow to move in train).

[Ed Rotondaro]

A lot of things about the Iowa's were never tested, Ed. We don't really know how good the seakeeping was until she went to the NA or a location other than the South and Central Pacific. Much of what what we have to go on, is theory and the SD class of BB's. We assume that if the SD's did well, so would the Iowa's. But their only adversary was a 20 year old battlecruiser upgraded to a battleship. Hard to know whether that was a fair representation of their abilities.

What battles in WWII can shed light on how post-WWI ship designers handled new problems in gunnery and aerial warfare? How can we judge the Iowa's?

Dennis:

Regarding sea keeping, I believe at least two of the class were present with Admiral Halsey when he ran into typhoons in the Pacific. I have not heard any adverse comments regarding their ability to handle stormy weather other than the bows being wet. This was also a problem for the the KGV class. HMS Vanguard may have been the best seaboat of the last generation of BBs.

[Ed Rotondaro]

Absolutely. There are many things to consider and that's why the best that can be said is the probability of an occurrance rather than an absolute. What would have happened had the 14 inch round hit the barbette directly? What's the probability of it penetrating? I certainly don't know. Here's what Nathan Okun says:


Dennis:

I was under the impression that the 14" shell that hit was not an AP shell, but rather a bombardment shell which would not have penetrated under any circumstances.

[old_pop2000]

Dennis:

Regarding sea keeping, I believe at least two of the class were present with Admiral Halsey when he ran into typhoons in the Pacific. I have not heard any adverse comments regarding their ability to handle stormy weather other than the bows being wet. This was also a problem for the the KGV class. HMS Vanguard may have been the best seaboat of the last generation of BBs.

USS Iowa had her shaft damaged and she had to put back to Hunter's Point Shipyard in San Francisco and she also lost her airplane, which would be normal for a storm like that.

[Ed Rotondaro]

USS Iowa had her shaft damaged and she had to put back to Hunter's Point Shipyard in San Francisco and she also lost her airplane, which would be normal for a storm like that.

Dennis:

I wonder how long it takes to replace a shaft on a ship that size?

[Kyle Holgate]

Dennis:

I was under the impression that the 14" shell that hit was not an AP shell, but rather a bombardment shell which would not have penetrated under any circumstances.

I believe it has been determined that it was indeed an AP round, though I cannot tell you where I got that from - perhaps Nathan Okun's site or on the Warships1 board somewhere or other. I spend too much time reading and not enough remembering where I read things! :confused:

[Ed Rotondaro]

I believe it has been determined that it was indeed an AP round, though I cannot tell you where I got that from - perhaps Nathan Okun's site or on the Warships1 board somewhere or other. I spend too much time reading and not enough remembering where I read things! :confused:

Kyle:

I'll check it out tonight.

[Kyle Holgate]

http://www.navweaps.com/index_tech/tech-092.htm

Discussion of hit on South Dakota - has to be an AP round as the other possible candidates would not have done what this shell did as far as other damage.

[old_pop2000]

Dennis:

I wonder how long it takes to replace a shaft on a ship that size?

I don't know, but our resident Nuclear propulsion engineer certainly should have a good idea.

Commander, where are you?

[john964]

I don't know, but our resident Nuclear propulsion engineer certainly should have a good idea.

Commander, where are you?
It depends was it just the prop or was the whole shaft damaged? If it was just the prop it could be done in 10 days to 2 weeks plus they might decide to do other things that may need to be done in the near future like repainting the hull or doing scedualed maintance slightly ahead of sceduale. You don't waste drydock space for so short a time. For a full shaft replacement your looking at 2-3 months depending how long the shaft is.

[old_pop2000]

It depends was it just the prop or was the whole shaft damaged? If it was just the prop it could be done in 10 days to 2 weeks plus they might decide to do other things that may need to be done in the near future like repainting the hull or doing scedualed maintance slightly ahead of sceduale. You don't waste drydock space for so short a time. For a full shaft replacement your looking at 2-3 months depending how long the shaft is.

USS Iowa returned to Ulithi for supplies and repairs on December 23-24, 1944. She had to return to Hunter's Point, SF for a major overhaul arriving on January 15,1945. She left SF on March 19th, 1945 to relieve the USS New Jersey on April 15,1945 off of Okinawa. So apparently it was a shaft removal and replacement as it took two months to repair.

Thanks for the help.

[bridav58]

Well tell me guys at the range of 8-12K what ship's armor is going to stop a 14' shell? Unless your maybe Yamato and probably then only her turret fronts.

[Ed Rotondaro]

http://www.navweaps.com/index_tech/tech-092.htm

Discussion of hit on South Dakota - has to be an AP round as the other possible candidates would not have done what this shell did as far as other damage.

Kyle:

Thanks, I'll re-read that.

[Kyle Holgate]

Well tell me guys at the range of 8-12K what ship's armor is going to stop a 14' shell? Unless your maybe Yamato and probably then only her turret fronts.

I haven't tried Mr. Okun's program vs every armor, but generally if it's a good strait on hit most BB armor isn't gonna hold an AP round. That being said you have glancing blows and ones as actually happened where it bounces off the deck and looses its Ap cap. Armor like South Dakota had, even at short ranges is better than armor like Kirishima had. Less likely to deflect a shell that isn't a full on hit.

[old_pop2000]

I haven't tried Mr. Okun's program vs every armor, but generally if it's a good strait on hit most BB armor isn't gonna hold an AP round. That being said you have glancing blows and ones as actually happened where it bounces off the deck and looses its Ap cap. Armor like South Dakota had, even at short ranges is better than armor like Kirishima had. Less likely to deflect a shell that isn't a full on hit.


Based on Okun's article and Navweaps information on the 14 inch gun of Kirishima, at the 10000 yards or less, the incident angle is less than 7.5 degrees. Striking velocity is around 1875 FPS. I doubt, at the angle, they could have hit the belt and the rounds were the diving APC shells, so they were not really designed to strike the armor belt directly. Again, its a matter of probability where they would have penetrated or simply been deflected or shattered on the belt. The belt was designed against 16 inch 45 rounds.

[Kyle Holgate]

Based on Okun's article and Navweaps information on the 14 inch gun of Kirishima, at the 10000 yards or less, the incident angle is less than 7.5 degrees. Striking velocity is around 1875 FPS. I doubt, at the angle, they could have hit the belt and the rounds were the diving APC shells, so they were not really designed to strike the armor belt directly. Again, its a matter of probability where they would have penetrated or simply been deflected or shattered on the belt. The belt was designed against 16 inch 45 rounds.

Run it in facehard, Nathan Okun's AP software. Ouch. Just don't get to point blank range on a BB if you can help it, I don't care what ship you're in! Maybe in Yamato's turret... but then what if hits a gun port instead of turret face? I think I like it right here at my desk...

[Ed Rotondaro]

Based on Okun's article and Navweaps information on the 14 inch gun of Kirishima, at the 10000 yards or less, the incident angle is less than 7.5 degrees. Striking velocity is around 1875 FPS. I doubt, at the angle, they could have hit the belt and the rounds were the diving APC shells, so they were not really designed to strike the armor belt directly. Again, its a matter of probability where they would have penetrated or simply been deflected or shattered on the belt. The belt was designed against 16 inch 45 rounds.


Dennis:

Based on the article, it appears that the first armor deck de-capped the shell and made it pretty near impossible to penetrate the barbette.