Mine warfare

[HBuhring]

Some questions I didn't find an answer to in the pdf manual:

1. Minelaying is a mission of its own: but how is minesweeping perfomed? Are minesweepers specialised mine warfare escorts and in this case are they different from minelayers (they were historically, even if most destroyers could perform both missions)?
2. Are mines persistent and for how long?
3. Is it possible to be damaged by your own minefields or is it assumed that you know the safe passages inside them?
4. Is there any difference between laying mines in coastal and deep-sea hexes?
5. Historically many navies used light cruisers in offensive minelaying duties. Why has it been decided that only escorts are capable of minelaying?
6. What is the max no. of mines you can deploy in a typical 48 nm hex? And how are odds that they will hit calculated?

Thanks again (and btw the manual is awesome: can't wait to see the game).

HB

[tony_glazebrook]

Some questions I didn't find an answer to in the pdf manual:

1. Minelaying is a mission of its own: but how is minesweeping perfomed? Are minesweepers specialised mine warfare escorts and in this case are they different from minelayers (they were historically, even if most destroyers could perform both missions)?
2. Are mines persistent and for how long?
3. Is it possible to be damaged by your own minefields or is it assumed that you know the safe passages inside them?
4. Is there any difference between laying mines in coastal and deep-sea hexes?
5. Historically many navies used light cruisers in offensive minelaying duties. Why has it been decided that only escorts are capable of minelaying?
6. What is the max no. of mines you can deploy in a typical 48 nm hex? And how are odds that they will hit calculated?

Thanks again (and btw the manual is awesome: can't wait to see the game).


HB

Thanks HB ;) In answer to your questions:
A1: all escorts can lay mines as well as sweep, but you can specialise them for the minelaying and sweeping role, making them more effective in this (but less so in ASW, torpedo and AA roles). Escorts also sweep during minelaying missions; there are no separate minesweeping missions as such - defensive minelaying missions both clear out enemy mines and lay your own defensive fields at the same time. And escorts in all fleets will automatically sweep as they go if the crusing speed is <= 12 knots
A2: yes - indefinitely (until removed by enemy sweeping)
A3: no, yes
A4: no
A5: just one of those many decisions to simplify things; we might look at changing this BUT bear in mind that the 'escort' type in SAS can go up to small light cruiser size - there is some cross-over there
A6: no maximum. Odds are calculated by a formulla that calculates for each ship the area traversed in a hex in an hour given its size and speed, the spacing of mines given their density (number per hex area), a certain randomness factor (as mines tended to be laid in fields rather than uniformly), plus an evasion factor that depends on the visibility and ship manoueverability and crew training. There is also some reduction to allow for dud mines.

[DiFool6]

Subs have historically laid a lot of mines, as they can do it stealthily.

[HBuhring]

Thank you for your answer. Soo many things I will love to play with in SAS...


Escorts also sweep during minelaying missions; there are no separate minesweeping missions as such - defensive minelaying missions both clear out enemy mines and lay your own defensive fields at the same time. And escorts in all fleets will automatically sweep as they go if the crusing speed is <= 12 knots
A2: yes - indefinitely (until removed by enemy sweeping)

... which in turn leads to another question: how effective is minesweeping? Are all enemy mines removed when an escort performs a sweep? And the presence of an escort at <= 12 kn is enough to ensure total immunity to any fleet passing thru that hex?

Cheers

HB

[tony_glazebrook]

Subs have historically laid a lot of mines, as they can do it stealthily.

The ability of subs to lay mines has always been on the radar screen; it just missed the cut for R1.0, but is a candidate for inclusion sooner rather than later, especially as it wouldn't require much work :-)

[tony_glazebrook]

Thank you for your answer. Soo many things I will love to play with in SAS...



... which in turn leads to another question: how effective is minesweeping? Are all enemy mines removed when an escort performs a sweep? And the presence of an escort at <= 12 kn is enough to ensure total immunity to any fleet passing thru that hex?

Cheers

HB

Escorts can sweep at a certain rate based on their size and whether they are specialist minelayers/sweepers, general purpose or specialist escorts in some other area (eg ASW). (The simple rule of thumb is that a GP escort has all round capability; escorts that specialise have double the capability in that area and half that in the other areas. The areas an escort can specialise in are: mine-laying/sweeping; AA; ASW; torpedo attack.

A fleet with escorts steaming through an enemy minefield can still suffer damage of course if mines remain after sweeping. Sweeping is rather slow and a dense minefield will remain a hazard for some time. I can't give you all the variables that determine how this is calculated. But mines ARE a very effective weapon. As an example, in playtesting Pacific scenarios, I have found that a Japanese computer opponent tends to lay mines at choke points around the Phillipines, and these do claim victims. Similarly. an aggressive US AI will try to lay mines also to interdict Japanese convoy routes between the mainland and Malaya and the Dutch East Indies, which can be effective also. And the ability to create minelaying missions easily through your 2IC, (and you can nominate objective hexes if you want instaed of leaving it to the computer to select them) takes the drudgery out of setting up what are potentially complicated mission orders (involving multiple trips out and back in the course of a full turn). I'm pretty happy with how mines are handled, though as I've said in another post, sub-laid mines is something I'll certainly consider for a R1.1 or R1.2...Before we commit to new features we will evaluate the range of feedback we get and then decide priorities.

Cheers HB

[Millsy]

Tony,

Can i put in an early request for you to also include minelaying by aircraft.

Campbell's Naval Weapons of WW2 gives following figs for GB


In enemy waters - Over 40k mines layed by a/c and 20k by ships/subs
defensively over 170k (mainly by ships)
(also says that the 48k laid by RAF sank 545 merchants (591k tons) and 217 warships (147k tons)

[tony_glazebrook]

Tony,

Can i put in an early request for you to also include minelaying by aircraft.

Campbell's Naval Weapons of WW2 gives following figs for GB


In enemy waters - Over 40k mines layed by a/c and 20k by ships/subs
defensively over 170k (mainly by ships)
(also says that the 48k laid by RAF sank 545 merchants (591k tons) and 217 warships (147k tons)

Thanks Millsy, I have noted this :-)

[Millsy]

and more to the point minelaying will give Bomber Command something to do that is not quite so ethically dodgy.

As an aside the only damage to S&G in the channel dash was as result of hurridly laid mines by a/c

[Christian Schwietzke]

Escorts can sweep at a certain rate based on their size and whether they are specialist minelayers/sweepers, general purpose or specialist escorts in some other area (eg ASW). (The simple rule of thumb is that a GP escort has all round capability; escorts that specialise have double the capability in that area and half that in the other areas. The areas an escort can specialise in are: mine-laying/sweeping; AA; ASW; torpedo attack.

A fleet with escorts steaming through an enemy minefield can still suffer damage of course if mines remain after sweeping. Sweeping is rather slow and a dense minefield will remain a hazard for some time. I can't give you all the variables that determine how this is calculated. But mines ARE a very effective weapon. As an example, in playtesting Pacific scenarios, I have found that a Japanese computer opponent tends to lay mines at choke points around the Phillipines, and these do claim victims. Similarly. an aggressive US AI will try to lay mines also to interdict Japanese convoy routes between the mainland and Malaya and the Dutch East Indies, which can be effective also. And the ability to create minelaying missions easily through your 2IC, (and you can nominate objective hexes if you want instaed of leaving it to the computer to select them) takes the drudgery out of setting up what are potentially complicated mission orders (involving multiple trips out and back in the course of a full turn). I'm pretty happy with how mines are handled, though as I've said in another post, sub-laid mines is something I'll certainly consider for a R1.1 or R1.2...Before we commit to new features we will evaluate the range of feedback we get and then decide priorities.

Cheers HB

Even if minesweeping was extremely effective... minefields would still act as a speed bump, forcing enemy TFs to slow down to 12 knots in order to allow escorts to sweep. This can completely ruin the "go in after dusk, go out before dawn" approach to fast transport and bombardment missions - among other things. AND at 12 knots even an otherwise fast battleship or carrier force will be slow enough for submarines to attack them.

[FAdmiral]

All the above posts were made before the game came out. I have seen the mines
in my intro campaign (testing) that my DDs have laid (placement & numbers) which
is good. What is NOT so good is that I can also see ALL enemy mines and how many?
Shouldn't there be more fog of war as to the placement of enemy mines and how
many are laid? Now I thought maybe my info on this was not entriely accurate and
I was getting false numbers & locations but after checking the Japanese side, I see
that everything was dead-on. I would think using the fog of war that my intel would
maybe estimate the placement of enemy mines but until my ships/subs actually went
there, I would not know exact locations (number of enemy mines should never be
exact, how would they know for sure)

JIM

[Scott Chisholm]

All the above posts were made before the game came out. I have seen the mines
in my intro campaign (testing) that my DDs have laid (placement & numbers) which
is good. What is NOT so good is that I can also see ALL enemy mines and how many?
Shouldn't there be more fog of war as to the placement of enemy mines and how
many are laid? Now I thought maybe my info on this was not entriely accurate and
I was getting false numbers & locations but after checking the Japanese side, I see
that everything was dead-on. I would think using the fog of war that my intel would
maybe estimate the placement of enemy mines but until my ships/subs actually went
there, I would not know exact locations (number of enemy mines should never be
exact, how would they know for sure)

JIM

Jim,

I probably need to defer to Tony, but you will see enemy mines in those hexes in which your ships have struck them. Could that be what you are seeing?

[FAdmiral]

No, where most of the enemy mines are, I have not ventured into those areas.
There were very heavy concentrations of Japanese mines over near the Java
area and points north. I have sent no ships into that area whatsoever. I have
seen enemy TFs over there, then the mines appear between turns. The AI can
also see all my mines and the exact number I laid. NO Fog of War here at all !!!

JIM

[tony_glazebrook]

All the above posts were made before the game came out. I have seen the mines
in my intro campaign (testing) that my DDs have laid (placement & numbers) which
is good. What is NOT so good is that I can also see ALL enemy mines and how many?
Shouldn't there be more fog of war as to the placement of enemy mines and how
many are laid? Now I thought maybe my info on this was not entriely accurate and
I was getting false numbers & locations but after checking the Japanese side, I see
that everything was dead-on. I would think using the fog of war that my intel would
maybe estimate the placement of enemy mines but until my ships/subs actually went
there, I would not know exact locations (number of enemy mines should never be
exact, how would they know for sure)

JIM


Jim - what you see regarding enemy mines are estimated numbers - the variance from reality is part random and mostly a reflection of your intel level

[FAdmiral]

Tony, thats what I first thought but when I fired up the Japanese side to check,
the numbers were exactly the same on both my mines and the enemys. All mines
exact from both sides...

JIM

[tony_glazebrook]

Tony, thats what I first thought but when I fired up the Japanese side to check,
the numbers were exactly the same on both my mines and the enemys. All mines
exact from both sides...

JIM


Hmm, that's odd. Unless you have extremely high intel (and the enemy, very low) there will be a % variance. If the numbers are low, then the variance is small, but should still be apparent. Was this a custom campaign? Do you know what the intel level on each side was? I'll review the code anyway but I'd like to know.

[FAdmiral]

I am playing the intro just to get a feel for the game till 1.03 comes out. The settings
for both me (USA) and the AI (Japan) are Cautious. We have both engaged in minelaying
near our respective bases. The AI DDs are larger than mine so he/it lays more mines
per mission. But inbetween turns when I click the mines check, I see it all exactly the
same from both sides???

JIM

PS. Tony, could it be that the "intro" (learning the game) mission have a reduced or absent "Fog of War" for teaching purposes?????
This might explain both this thread and the one about very high intel on enemy fleets. Just a thought !!

[Drake420]

Lets see them get my convoys now! :p

http://img26.imageshack.us/img26/2136/mines2wp0.th.jpg (http://img26.imageshack.us/my.php?image=mines2wp0.jpg)

[goodwood]

None of your ships will get through either. you just sent your economy broke! Mines cost money in the real world, and perhaps thats something Tony should look at, before every hex in the pacific is unrealistically mined.
Ron

[Drake420]

None of your ships will get through either. you just sent your economy broke! Mines cost money in the real world, and perhaps thats something Tony should look at, before every hex in the pacific is unrealistically mined.
Ron

Well to be fair, each hex only has from 150-600 mines.(probably averages around 400) and my convoys dont have a problem as they cannot be damaged by my own mines.

The supply drain is an Issue, Its hard to say really if it needs to be increased for mines though.(it might be worth taking a close look at though) basically I have to choose between fuel for my ships, or more mines :p

Once I have some more Dedicated supply ships it wont be a problem though.


And keep in mind I have been laying them for 2 years now. It was my first priority to lay mines and secure my raw material convoy routes. A more agressive America might have taken advantage of this with subs to starve my lesser protected supply convoys to Truk and Rabaul and I would not have been able to fuel my battleships and carriers.

So far I have sunk 26 American ships with the mines, 24 of which were subs.

Basically this is my test campaign. what I have learned will come in handy when 1.0.3 is released and I will play vs Aggressive America.

Edit: BTW, For the most part of the war I have been running 4-6 Mine laying Task forces. 8DDs each. over 2 years and alot of manual orders you can make quite the defense wall.

[goodwood]

Well to be fair, each hex only has from 150-600 mines.(probably averages around 400) and my convoys dont have a problem as they cannot be damaged by my own mines.

The supply drain is an Issue, Its hard to say really if it needs to be increased for mines though.(it might be worth taking a close look at though) basically I have to choose between fuel for my ships, or more mines :p

Once I have some more Dedicated supply ships it wont be a problem though.


And keep in mind I have been laying them for 2 years now. It was my first priority to lay mines and secure my raw material convoy routes. A more agressive America might have taken advantage of this with subs to starve my lesser protected supply convoys to Truk and Rabaul and I would not have been able to fuel my battleships and carriers.

So far I have sunk 26 American ships with the mines, 24 of which were subs.

Basically this is my test campaign. what I have learned will come in handy when 1.0.3 is released and I will play vs Aggressive America.

Edit: BTW, For the most part of the war I have been running 4-6 Mine laying Task forces. 8DDs each. over 2 years and alot of manual orders you can make quite the defense wall.

Drake
I must admit when it comes mine warfare I know very little, but the economics and the limited resources of manpower and machinery, would prevent any navy during WW2 to lay that kind of carpet.
Ron

[Scott Chisholm]

Drake
I must admit when it comes mine warfare I know very little, but the economics and the limited resources of manpower and machinery, would prevent any navy during WW2 to lay that kind of carpet.
Ron

Actually, laying mine fields is easy (I work at a USN Minesweeping squadron); it's just a function of rolling the mines off the back end of the ship. You need to have a pretty good idea where you put them if you intend to transit the minefield, but other than that, it's a piece of cake. Also, mines are not very expensive, especially the moored mines used in WW2. They are perhaps the most cost-effective weapon ever produced.

Sweeping them, on the other hand, is a serious PITA, and is why all hands not needed below decks frequently assembled on the main deck during sweeping operations - just in case something went "bump".... :eek:

[FAdmiral]

Don't moored mines have to be in fairly shallow water? I doubt if many mines were
attached to mile long cables. And, of course, you just can't let them float FREE !!
Then they would be a hazzard to all shipping, regardless of nationality....

JIM

[goodwood]

Actually, laying mine fields is easy (I work at a USN Minesweeping squadron); it's just a function of rolling the mines off the back end of the ship. You need to have a pretty good idea where you put them if you intend to transit the minefield, but other than that, it's a piece of cake. Also, mines are not very expensive, especially the moored mines used in WW2. They are perhaps the most cost-effective weapon ever produced.

Sweeping them, on the other hand, is a serious PITA, and is why all hands not needed below decks frequently assembled on the main deck during sweeping operations - just in case something went "bump".... :eek:

Sorry Scott you may missed my point, that image Drake has posted, indicates about 90% of the South China Sea has had mines laid in it. Even with my limited knowledge of this subject that sort of thing didn't happen, If either side historically laid that many mines in and around the Straits of Gibraltar a ship from either side would not have entered the Med.
Ron

[Warship NWS]

Some facts.. 10% of the allied/neutral shipping lost during WW2 was due to mine warfare and the 3rd leading cause of shipping losses at 534 ships (1.4M tons) - more then raiders, warships, and coastal craft combined. In the first 7 months of naval warfare over 50% of the naval losses were due to mines.

Some facts:

The Straits of Gibraltar were mined and swept during WW2. The Germans would lay quick minefields using subs and the RN had to come out and clear them.
Palau was given up as a naval base by the Japanese after the use of USN tactical mining (bottling up the ships in the harbor) and bombing by aircraft.
The British were estimated to have laid 260,000 mines during both WW2 defensive and offensive mining operations.
In the Pacific the IJN laid an estimated 50,000 mines and the USN 44,000 mines.

So the question would be.. what is considered historically plausible or totally impossible?

If a military power wanted to invest large portions of their resources to mine warfare there was little to stop them. So long as accurate maps were retained to allow freindly shipping to find safe passage a naval power could invest considerable military assets to laying very extensive minfields - WW1 proved this fact and many major warships (18 CRs to BBs) were sunk due to mines.

[Warship NWS]

Naval fact, the Mk6 moored mine developed during WW1 for North Sea mining operations was capable of deployed in up to 3,000' of water. It was still in the USN inventory up to 1985.

Mines types varied but the most common were floaters, influence, bottom laid (shallow water anti-sub mines for example), and moored mines. It all depended on the tactical requirements, however, moored mines could be deployed to whatever depth was practical for the length of the precut or preset anchored cable.

[goodwood]

Some facts.. 10% of the allied/neutral shipping lost during WW2 was due to mine warfare and the 3rd leading cause of shipping losses at 534 ships (1.4M tons) - more then raiders, warships, and coastal craft combined. In the first 7 months of naval warfare over 50% of the naval losses were due to mines.

Some facts:

The Straits of Gibraltar were mined and swept during WW2. The Germans would lay quick minefields using subs and the RN had to come out and clear them.
Palau was given up as a naval base by the Japanese after the use of USN tactical mining (bottling up the ships in the harbor) and bombing by aircraft.
The British were estimated to have laid 260,000 mines during WW2 in both defensive and offensive mining operations.
In the Pacific the IJN laid an estimated 50,000 mines and the USN 44,000 mines.

So the question would be.. what is considered historically plausible or totally impossible?

If a military power wanted to invest large portions of their resources to mine warfare there was little to stop them. So long as accurate maps were retained to allow freindly shipping to find safe passage a naval power could invest considerable military assets to laying very extensive minfields - WW1 proved this fact and many major warships (18 CRs to BBs) were sunk due to mines.

Chris

I don't want to harp on this issue, but I do like things appear realistic. Let quote figures that maybe way out due to my lack understanding of several things. The area that Drake shows on his Jpeg image has a minimum of 200 hexes and a maximum of around 360 hexes. Each hex is 156km x 156km = approx 24000 square Kms. If one mine per square Km was deployed (very low density I assume) that's 24000 mines per hex, or a minimum 4.8 million mines for that area or a staggering 8.65mil maximum. The best british mine layer carried about 150 mines. taking into account that each mine laying TF would take say a conservative guess of 5 days to complete a mission including re arming. It would take 32000 ships to deliver 4.8 mil mines which = 1.6 mil ship days. It would take 500 ships 8.5 years to lay all those mines. Staggering, and that having ONE mine rer square Km. I may be wrong, but that density wouldn't kill too many ships. In summary between .6 and 1 mil mines were laid by all combatants by all modes of delivery, so unless my maths are incorrect ( more than an even chnce they are) the example shown by drake is totally impossible, and very unrealistic without even taking serious densities into account. Because of the 98 x 98 mile hexes there is a good chance should be able to sail past minfields undamaged.
sorry for the waffle
Ron

[Warship NWS]

To Ron,

Read his post again.. he stated an average of around "400 mines" per hex so at 200-360 hexes, according to your estimate, that is only 72k to 144k of mines being laid - the RN laid 260k mines during WW2 alone historically in 5 years time - most of them within the first half of the war to help counter subs and as offensive and defensive barrage fields. So if a navy decided to really ramp up mine warfare and paid the resource cost for doing so .. how is 144k of mines in 2 years out of bounds if we are using historical figures as a guage?

Thanks.

[goodwood]

To Ron,

Read his post again.. he stated an average of around "400 mines" per hex so at 200-360 hexes, according to your estimate, that is only 72k to 144k of mines being laid - the RN laid 260k mines during WW2 alone historically in 5 years time - most of them within the first half of the war to help counter subs and as blockade measures. So if a navy decided to really ramp up mine warfare and paid the resource cost for doing so .. how is 144k of mines in 2 years out of bounds if we are using historical figures as a guage?

Thanks.
Yep Chris I understand that, but equals 1 mine every 24 sq miles, that's like dropping a bomb with cluster mines in the middle of a dessert and expecting a grunt to walk on it, it just aint gonna happen very often.
In 98 mile hex a navy needs lay more than 400 mines to get a high probability of a hit. Obviously there must be some abstracting in scale of this size for hit and miss probabilities, but these abstractions must apply to the of hexes that can laid in any period of time.
Ron

[Warship NWS]

Yep Chris I understand that, but equals 1 mine every 24 sq miles, that's like dropping a bomb with cluster mines in the middle of a dessert and expecting a grunt to walk on it, it just aint gonna happen very often.
In 98 mile hex a navy needs lay more than 400 mines to get a high probability of a hit. Obviously there must be some abstracting in scale of this size for hit and miss probabilities, but these abstractions must apply to the of hexes that can laid in any period of time.
Ron

I understand what your trying to convey.. in his case though, he is laying very low density mine fields so his probabilties of any successes is likely very low. What we need here is verifiable evidence that something is wrong before we go hunting for a problem. Based on what he reported so far I do not see any verifiable evidence of a major issue. If he wants to lay a few scattered mines around in each hex.. well, it can be done. What I can bring up for our internal discussions is possibly a density rating per hex as a visual cue.. say, a colored mine icon - green for low density, yellow for moderate density, red for heavy density - scaled per hex size and quantity of mines of course. I will see what comes up within our discussions.

Thanks.

[Drake420]

I understand what your trying to convey.. in his case though, he is laying very low density mine fields so his probabilties of any successes is likely very low. What we need here is verifiable evidence that something is wrong before we go hunting for a problem. Based on what he reported so far I do not see any verifiable evidence of a major issue. If he wants to lay a few scattered mines around in each hex.. well, it can be done. What I can bring up for our internal discussions is possibly a density rating per hex as a visual cue.. say, a colored mine icon - green for low density, yellow for moderate density, red for heavy density - scaled per hex size and quantity of mines of course. I will see what comes up within our discussions.

Thanks.

Actually they seemed to work quite well for me.

I think one of the reasons is that while they may be low density, the enemy has to cross many hexes before reaching my convoys.

So far I have sunk 25 enemy subs with the mines, most of which were in a few months. Since then they haven't bothered me quite as much. Im not sure if this is the AI realizing its suicidal to attack my convoys, or if they just ran out of subs.

So far I have only lost 5 merchant ships, all size 1. 4 of which were outside of the safe area, so I think that shows the effectiveness of mining your convoy routes.

This is against the standard cautious setting of the American AI. This strategy may not have worked as well against a more aggressive AI. My next campaign (once 1.0.3 is released) will be against a more aggressive AI. I will post my results of that campaign as well.

Personally im not sure whether the mine system needs tweaking or not, Im no expert on mine warfare. No complaints here ;)

[Warship NWS]

Considering the numbers of mines laid, density, and area coverage.. 25 being sunk is about right when considering your covering 2 years of naval war when you compare those numbers to historical figures where dozens of subs/ships were lost in dense minefields covering much smaller areas of ocean.