Tactics??

[Bulkhead]

Hello sailors.

Is the destroyer capable to detect my sub when I am behind it? I heard that its impossible to detect even a sub at full speed because of his own propeller noice..
World war 2 speaking of course...

[AVGWarhawk]

The DD did forward sweeping with sonar. Yes, the props in the stern would certainly screw up hearing much of anything. In the baffles as it were.

[Bulkhead]

So a good idea is to go to 200 ft or so until they passed above me and try to follow them and go for a kill???

Or does anyone have better ideas??

[Ducimus]

http://www.ducimus.net/sh4/ai.htm

edit: oh, btw, lost contact time, and thermal layers do not work the same as is described in this link.

[Peto]

Bulkhead: The tactics for subsims are varied due to the innumeral variables posible (weather/sea state/AI experience/etc). Your idea of following an escort has worked for me but I typically use it whem I'm trying to get away. If I'm having trouble breaking contact, I will sometimes follow a Destroyer in an effort to clear the area I was in when I was last attacked. The trick is knowing when to go silent again because there's no doubt he'll be turning back my way. And I don't even bother trying it with smaller escorts because their turning radius is so small.

After years of playing subsims, I've found that sometimes it just comes down to rubbing my rabbit's foot for luck :yep:.

Happy Hunting!!!

[SteamWake]

As a means of practical illustration go to your own sonar station and sweep through 180 degrees.

You will notice the ambient noise level goes way up... even at 1/3 ahead. To me that blind spots seems a little narrow but I have no data to back it up yet its still there.

The ships have the same blind spot.

Also might want to note that a DD charging ahead at flank cant hear much of anything anywhere. Technically because of water rushing over the hydrophone heads. I dont think the same holds true for active sonar though.

Typically a DD will slow down or even drift when there listening. Ive seen them work in pairs one charges and drops cans while the other drifts and listen. A precarious situation to say the least.

[Bulkhead]

Ok, so for a destroyer its not enuff to stop the props for a short moment, it have to slow down as well......?!?

Yes, get out of there is my choice of action too, but i came across two huge liners that i wanted on my tonnage-sunk-list.
The two liners where protected by 4 destroyers.

When i got them on my radar i dived and listen. As they got closer i dived further down to 200 ft to get under the "thermal layer", i used my ping sonar some times to determine how far away.
4-6000 yrds i got up to periscope depth without using the props. The destroyers starts to ping me and i have to go back down to 200 ft and move a little bit out of the lane.
After 15-20 mins the two liners are right over me and passing whithout the destroyers finding me.
I wait for a few more mins, and go back up to periscope-depth.
Now i am in an angle from behind the liners, but the destroyers zig-zagging is working obviously, and i ending up using my torpedo loadout at them instead of the two heavy liners.....YES. it was TWO!!!!

How would anyone of you do this scenario?

[DeepSix]

Hmm.... I'd rather have the liners. If the destroyers are unlucky enough to be sailing a straight course across my bow, that's their problem. More often than not, I elect to make a clean attack on merchants and then go deep and ignore the escorst. Destroyers have so little tonnage that they're usually better evaded than attacked (IMO).

[kylesplanet]

Ok, so for a destroyer its not enuff to stop the props for a short moment, it have to slow down as well......?!?

Yes, get out of there is my choice of action too, but i came across two huge liners that i wanted on my tonnage-sunk-list.
The two liners where protected by 4 destroyers.

When i got them on my radar i dived and listen. As they got closer i dived further down to 200 ft to get under the "thermal layer", i used my ping sonar some times to determine how far away.
4-6000 yrds i got up to periscope depth without using the props. The destroyers starts to ping me and i have to go back down to 200 ft and move a little bit out of the lane.
After 15-20 mins the two liners are right over me and passing whithout the destroyers finding me.
I wait for a few more mins, and go back up to periscope-depth.
Now i am in an angle from behind the liners, but the destroyers zig-zagging is working obviously, and i ending up using my torpedo loadout at them instead of the two heavy liners.....YES. it was TWO!!!!

How would anyone of you do this scenario?

I to usually just let the destroyers go (unless I have a really good close shot and plenty of fish) but one thing you might want to keep in mind, every time you use that ping sonar around a DD you basically give away your position and if they happen to be the "elite" DD's, that can be a problem to say the least. I like to stay under the thermal layer until the lead DD passes then call battlestations and raise to periscope depth. I raise my scope just long enough for visual conformation. If they are still not where I want, I lower it and wait. After I fire all my intended fish, I dive deep and turn under the convoy so their noise makes it harder to pinpoint me. Always keep it about 2-3 knots, silent running the whole time of course.

[Bulkhead]

Thanks:)

I use ping some times for now, i am not used to the sounds and judging distance just by listening yet. But i will hopfully learn it good after a while.

I try the ping also at long distance, timing the echo. But thats difficult to get accurate. The ping gauge is only 4000 ft i think..
:)

[SteamWake]

Thanks:)

I use ping some times for now, i am not used to the sounds and judging distance just by listening yet. But i will hopfully learn it good after a while.

I try the ping also at long distance, timing the echo. But thats difficult to get accurate. The ping gauge is only 4000 ft i think..
:)

Careful with those pings. Under the right conditions it can be like ringing the dinner bell for Jaws.

[captiandon]

Man I always do the oppiset. When I want to sink A DD I try to get his attention. I run ahead of him a PD at FS With the Gramaphone blasting Glenn Miller so he knows its me. When I get him lined up at 180 I fire a single shot, That at most is enough to sink him, All tought I have yet to try that after loading NSM.

[Bulkhead]

I do that too often, but on a loadout og 6 torps is not enuff for 4 destroyers and 2 liners.

[capt_frank]

http://www.ducimus.net/sh4/ai.htm

edit: oh, btw, lost contact time, and thermal layers do not work the same as is described in this link.

A most excellent read! I was wondering why those bastages were "seeing" me in soiten circumstances...:gulp:

Thanks!

[MorganThePirate]

As all of us know World War 2 submarines had quite limited underwater speed, range, and endurance. They usually sailed on the surface, especially at night, and submerged only when they had to, to avoid being detected and attacked.
Japanese antisubmarine forces consisted mainly of their destroyers, with sonar and depth charges. However, Japanese destroyer design emphasized surface night fighting and torpedo delivery over anti-submarine duties. By the time they finally developed a destroyer escort which was more economical and better suited to convoy protection, it was too late to save their shipping lanes. The Japanese Army also developed two small aircraft carriers and Ka-1 auto gyro aircraft for use in an antisubmarine warfare role.
The Japanese depth charge attacks by its surface forces initially proved fairly unsuccessful against US fleet submarines. Unless caught in shallow water, a US submarine commander could normally escape destruction, sometimes using temperature gradients (thermo clines). Moreover, IJN doctrine emphasized fleet action, not convoy protection, so the best ships and crews went elsewhere. During the first part of the war, the Japanese tended to set their depth charges too shallow, unaware US submarines could dive below 150 feet (45m) :know: :oops: :p . Unfortunately, this deficiency was revealed in a June 1943 press conference held by US Congressman Andrew J May and soon enemy depth charges were set to explode as deep as 250 feet (76m) :damn: :damn: :damn: . Vice Admiral Charles Lockwood later estimated May's revelation cost the navy as many as ten submarines and 800 crewmen. Much later in the war, active and passive sonar buoys were developed for aircraft use.
I think also that the Japanese antisubmarine forces used the magnetic anomaly detectors that they were first employed to detect submarines during World War II. Also the US used them.. MAD gear was used either towed by ship or mounted in aircraft to detect shallow submerged submarines :hmm: .
To reduce interference from electrical equipment or metal in the fuselage of the aircraft, the MAD sensor is placed at the end of a boom or a towed aerodynamic device. Even so, the submarine must be very near the aircraft's position and close to the sea surface for detection of the change or anomaly. The detection range is normally related to the distance between the sensor and the submarine. The size of the submarine and its hull composition determine the detection range. MAD devices were usually mounted on airplanes.:arrgh!: