You're a sub. You want to sink the destroyer above you...

...a destroyer bent on either sinking you or forcing you to the surface. How would you do it?

 

Depends on a lot...plenty of luck for a start...I’ve always wondered about specially made mines for subs...think two rows of mines 4-5 in each row. Sitting on the aft deck (maybe semi sunk into the deck - but not critical). These mines have a buyouncy bladder that when activated shoot straight to the surface...was this ever thought of?
Let them go as the destroyer bears down, then quickly change direction and (not so quickly) depth...
I’m thinking a mine about half again a soccer ball...

 

Depth charges in reverse??

One risky method was the down-the-throat shot - let the destroyer come right at you, maybe even leave the periscope up so he knows where you are. There's no left or right motion, no fancy calculations, just a straight shot at a target 30-40' wide. Fire at minimum range (torpedos have a safety device which doesn't let the exploder activate until they're a safe distance from the sub, say 300-500 yards). Hope the exploders work properly! A reliable magnetic exploder would be ideal, but as we know that was not the case in WWII. Sam Dealey, the "Destroyer Killer", got at least one of his kills that way.

 

Late war there were some wake homing torps I believe. Working with another sub can also help especially if they don't know there are more than one.

 

As I said, depends...this is assuming the sub already has the minimum distance, and hasn’t dived...also as the destroyer bears down, the ‘minimum’ distance for the torps is actually further out...as the destroyer closes the distance.
I could go on about diving deep, looking for hot and cold water streams, going quiet and waiting until the destroyer either went away, slowed or stopped and without engines, float up to periscope depth and take a quiet shot...but this all depends on many things...many things...so your parameters would have to be stricter IMO to have an opinion on what to do...

 

Call a carrier?

 

Half a soccer ball of explosive would not do much to a destroyer. Even less considering the half soccer ball would mostly be an air bladder.

Still, the crew might die of laughter.

 

You would't, you would make like a hole in the water, and be happy if you escaped with boat and crew intact.

You could pull a John Wayne and battle surface to shoot it out with the destroyer, but that rarely ended well for the submarine.

 

I don't know much about U-boat tactics in WW2, but avoiding destroyers, or anything that is sufficiently capable of defending itself is, was ideal and the smartest course of action.

 

I don't think there were wake homers in WWII, but the Germans had acoustic torpedos which could home in on a ship's propellors. Naturally this usually generated a hit in the stern, which could leave an escort immobilized in mid-Atlantic if not sunk outright.

The US also had a homing torpedo used by subs late in the war and an airborne torpedo with the cover name "Mark 24 mine" and nickname "Fido" for use against submarines.

 

The US submarine launched acoustic homer was the Mark 27 "Cutie."

 

And if I recall correctly from "Thunder Below", Eugene Fluckey had a very low opinion of it. His writings about the use of the "Cutie" are very interesting.

 

I guess if the destroyer was with a convoy the Sub's best chance was to go deep and silent. The destroyer could not leave the convoy alone as soon there would be more subs and some captains even drove inside the convoy and started their hunt there.

 

I'll take that as a "Yes CAC that sounds like a good idea" - Half AGAIN (1 and a half) not half a soccer ball...it could be bigger couldn't it? Yes of course it could. The bladder needs only to be small...they can raise a whole ship using relatively small bladders...it doesnt take much.

 

What...They don't have beach balls in Australia?

OK, I'll humor you...
The largest regulation soccer ball is .22089 cubic feet. A cubic foot of water weighs 62 pounds. That will give us a displacement weight of roughly 13.7 pounds. Now.we'll multiply that by 1.5(half again) for about 20.55 pounds.
Thus our amount of explosive carried is 20.55 pounds.

But, wait...That is just neutral bouyancy. Not "shooting to the surface" bouyancy.

Now, the question will be how much explosive weight do we sacrifice for "shooting to the surface buoyancy?

 

Your quibbling...the idea is sound, or at least you are yet to give a reason for it not to be...the buoyancy is an easy problem to solve. the only question is what is the minimum size (explosive) and what type of explosive will actually damage what is usually a relatively thin hull. Forget the soccer ball...it was only to give an idea of what size was in my head...if it suits lets say it carries "normal" sea mines...happy?

 

I wasn't commenting on the soundness of the idea. I was commenting on your borked sense of proportion.

The soundness of the idea is highly situational.

Given that a submarine's sonar blind spot is aft, you have no idea of the destoyer's location, or more importantly, distance from you...So, one will have to remain no greater than periscope depth to accurately release.

Also, you best course of evasion, might just be straight ahead, as the destroyer will likely turn to avoid them.

Given that they are stored outside the pressure hull...How susceptible to sympathetic detonation will they be to depth charges.?

Of course , these mines are negated with the advent of ahead-thrown weaponry.

But, they biggest con is that you've screwed the pooch when this does not work. At least with a torp shot, you still have plenty of Down Express time to get fertile seperation between your sub and the destroyer.

 

Of course its situational...everything is.
The sonar/sound operator can give a good idea of the above craft's position especially if close...not worth his salt if he cant. This whole situation is in response to the destroyer or other large craft trying to follow the sub's course and drop mines over the top of it...you've heard of this im sure. The mines could be constructed to resist "sympathetic detonation" - not difficult, come on.
Ahead thrown ordnance still requires the craft to follow the path in most cases, SIDE thrown mines would be the negating and correct response from the surface craft.
"biggest con is that you've screwed the pooch when this does not work" - One is already in plenty of trouble if they know your position well enough to go over to the top of the sub...its a way of responding (when there is no other option to retaliate) and diseuading the above craft to run the subs course. "When it doesn't work" - Why wouldn't it work? The torp shot doesn't work below a certain (shallow) depth its NOT an option in most of these scenerios...and by far the most dangerous option.
Why not try to think of a way this WOULD work instead of being Mr. Contradiction? A tiresome fellow is Mr Contradiction.

 

I confused "wake homing" with "accustic homing" that said some of the mentions of homing torpedoes at:
World War II Torpedoes of the United States of America - NavWeaps
don't specify what they were homing on. At least one mentioned was developed at least partially during the war but not put in service until afterward

This page mentions the Germans used about 640 homing torpedoes during the war:
Torpedoes of Germany - NavWeaps
.