AOD & SH1 Escort Behavior?

[MarkShot]

I was just curious if anyone knows why escorts in AOD are in continuous search mode with their ASDIC for subs and escorts in SH1 only turn on active sonar when they are alerted to the presence of a sub?

What was the design reasoning behind that difference?

Which policy is historically accurate?

Thanks.

[Sailor Steve]

AOD's constant search mode felt more realistic to me, though I couldn't say with 100% certainty. I'm pretty sure escorts were always on the lookout for subs, rather than waiting until something happened. While Sonar/Asdic had it's limitations, there was a chance that a sub would be picked up at a range of 20 miles or more. On the other hand, a whale could be picked up and the escort might roll right over a sub on it's way to investigate the 'contact', and never no the real threat was there.

The convoy might be going six knots; the escorts could effectively 'ping' up to twelve knots, or more late in the war.

[MarkShot]

Well, I have been playing some SH1 as of late.

The fact that escorts aren't automatically pinging away makes it much easier to penetrate a screen. Of course, once you fire that first salvo, then things start getting interesting.

In AOD, it seems pretty hard to penetrate a heavy screen coming in at PD. The best methods I have found for heavy screen penetration are:

(1) Surface attack at night in heavy fog where visibility is very poor.

(2) Going deep below 200M and coming in slow underneath screen and coming back up to PD as the convoy begins to pass overhead.

[Bertgang]

I am with Sailor Steve here; an escort waiting since some merchants are sunk or damaged to start his survey shouldn't have made a great job.

Speaking of Aod, the surface attack in poor visibility becames the worst tactic after mid 1942 about as, thanks to radar, escorts are able to see in such conditions really better than you.
Some attempts are still possible by time but, in a general way, best to forget this method (really great early in the war).
Waiting in the deep is often the best thing to do, when your work isn't wasted by an unexpected course change of the convoy.

[Hitman]

I don't think a continuous use of ASDIC is a useful tactic for detecting subs that are not previously located in a more or less accurate position, but it certainly warns them about the convoy being escorted and makes it more frightening to search for a hole in the screen. It's like an animal that inflates itself and yells when menaced...it tries to look bigger and scarier than it is in reality.

From what I have read about japanese escorts in WW2 it is true that ASDIC -when available- was not always turned on. It was far more usual in both japanese and allied ASW vessels to do stop-and-run tactics, by steaming at high speed forward, then stopping machines and listening with passive for a while.

Anyway it seems that approaching a japanese convoys was relatively easier than doing so to an allied one, due to worser ASW training and tactics.

:hmm:

[MarkShot]

Here I am 1,500 yds from an 18,000 ton tanker protected by 7 escorts. Undetected until I launched my torpedoes.

I don't think I could have ever made such an approach in AOD.

Perhaps, foolish, but I attacked (I was up for the challenge). The Seahorse (SS-304) was sunk by Japanese depth charges after evading for about an hour.

http://mywebpages.comcast.net/markshot/tempimages/sh7es.jpg

[Bertgang]

Speaking of AoD escorts, I noticed they have poor or no coordinated tactis when radar equipped.

When a surfaced sub is detected, most of times each of them starts the hunt as if it could be the only combat unit running over your shadow; so, if you run flank speed just a bit more fast than enemy units, sometimes you are able to attract the whole hunting group behind your stern, and maybe to make a successfull surface attack against the now defenceless convoy.