Sonar question

[Ed Rotondaro]

Hi guys:

I have a question regarding sonar. Is the bow mounted sonar less effective than a towed sonar array? Do only DDs and FFGs carry sonar? I know we have some ex-sonar guys on board, os I'm sure someone will get up to speed. Thanks!

[Warship NWS]

Much depends on the quality of sonar, ocean conditions, and what your trying to detect - mines, subs, etc. Towed is, for the most part, the most effective method of detecting subs but you can only go so fast with it. Most towed arrays can be set for various depth settings so as to allow the detecting platform to move above the thermal layer while the array is below the layer. For ships, this may be their only real effective method, other then helos using dipping sonars, for detecting subs at deeper depths. Also, towed have a 360 degree coverage whereas bow sonars do not due to engine/propellers to the rear platform using it. Towed sonars, unless equipped with it, also do not usually have an active method of detection and are not usually very usefull for detecting mines.

As to what ships carry what types of sonars.. depends on the mission and design of the ship.

Thanks.

[Rick]

Chris , you need to learn to be more succinct in your answers. ;)


Is the bow mounted sonar less effective than a towed sonar array? Do only DDs and FFGs carry sonar?

Yes, no

[Warship NWS]

Actually, a flat "yes" is not that accurate for the first answer. Some VDS sonars, which are towed in some cases, are NOT as effective as bow sonars. It all depends on the quality of the sonar. Overall, in most cases, the towed sonar is more effective.. unless your trying to detect mines or, in some cases, your in noisy water. Sorry, I usually give simple answers.. if the question requires only a simple response. ;)

[Rick]

:p and just to give a straight answer.... Chris is spot on,

generally passive bow sonar is pretty useless, theres too much interference from flow noise and own ship noise except at very slow speeds. (although you could get an awsome broadband hit off fighter jets flying overhead when we were behind the carrier on plane guard) Active pinging is where bow sonars excel, the advantage being that you can get a firing solution much quicker than off a towed array, which reqires (often) lengthy target motion analysis to get a good shot. Passive also can have longer range, though the difference is not neccisarly great in all conditions. A good compromise was the old SQS-35 VDS with the SQR-17 attached to it (on Knox FF's)which could active ping from the VDS and also go passive off the 17.

[Warship NWS]

For ships with no towed arrays the tactic presently is to active ping at various intervals, or continuously depending on the threat assessment, due to the quietness of modern diesel and ultra-quiet nuke submarines. Submarines, depending on their age, maintenance, and sonar suite will almost always detect the ASW ships long before the ASW ships detect them in return. The active pinging tactic is an attempt to try and at least give the ASW assets a chance to get a chance to attack the sub before the sub can attack with torpedoes, or to "spook" the sub into reacting in a way that might allow the ASW assets a better chance to detect it, or just simply to force it out of an optimum position of attack. Various tactics are also used by ASW helos to try and help keep a sub at bay or to force it to react to the sonobuoys. Active sonar is in turn somewhat countered by anechoic tiling on the subs that helps to reduce the return signals of the active sonars. As it always goes.. the ultimate of cat and mouse detection games and battle of wits.

[john964]

For ships with no towed arrays the tactic presently is to active ping at various intervals, or continuously depending on the threat assessment, due to the quietness of modern diesel and ultra-quiet nuke submarines. Submarines, depending on their age, maintenance, and sonar suite will almost always detect the ASW ships long before the ASW ships detect them in return. The active pinging tactic is an attempt to try and at least give the ASW assets a chance to get a chance to attack the sub before the sub can attack with torpedoes, or to "spook" the sub into reacting in a way that might allow the ASW assets a better chance to detect it, or just simply to force it out of an optimum position of attack. Various tactics are also used by ASW helos to try and help keep a sub at bay or to force it to react to the sonobuoys. Active sonar is in turn somewhat countered by anechoic tiling on the subs that helps to reduce the return signals of the active sonars. As it always goes.. the ultimate of cat and mouse detection games and battle of wits.

I once asked my ships sonar officer what ASW was like, he said it was like hunting rattlesnakes at night with a flashlight and a shotgun. Basicly the first to see and get a shot off will win.

[Kyle Holgate]

From my experience ASW is hours and hours of pure boredom punctuated by episodes of very, very intense work. This is from a surface ship perspective (often referred to by sub jockies as targets). Either way, passive sonar contacts take a lot of time to "work" in which e v e r y t h i n g seems to go really slowly. My understanding from friends that were on subs - their sonar work is slow too.
Active sonar work is a whole different ball game. Graned all we did was "play war" with subs, but when you've got one close enough to be on active sonar you're in a knife fight. My take is that you want to keep the sub as busy as you can with your Helo (if your ship has one) and short ranged torpedoes from the ship, don't let the thing settle down long enough to put a fish into you. Ideally get the $*#* out of dodge and let your helicopter go after it while your ship is out of torpedo range!

As for the question of which is better - bow or towed - My belief is that the best bow sonar is not as good as the best towed sonar. Reasons already given (water noise on the bow, etc).

[Ed Rotondaro]

From my experience ASW is hours and hours of pure boredom punctuated by episodes of very, very intense work. This is from a surface ship perspective (often referred to by sub jockies as targets). Either way, passive sonar contacts take a lot of time to "work" in which e v e r y t h i n g seems to go really slowly. My understanding from friends that were on subs - their sonar work is slow too.
Active sonar work is a whole different ball game. Graned all we did was "play war" with subs, but when you've got one close enough to be on active sonar you're in a knife fight. My take is that you want to keep the sub as busy as you can with your Helo (if your ship has one) and short ranged torpedoes from the ship, don't let the thing settle down long enough to put a fish into you. Ideally get the $*#* out of dodge and let your helicopter go after it while your ship is out of torpedo range!

As for the question of which is better - bow or towed - My belief is that the best bow sonar is not as good as the best towed sonar. Reasons already given (water noise on the bow, etc).

Kyle, Chris and John:

Thanks for the insights, I appreciate the ability to learn more.