Anti-Destroyer tactics

perseus

perseus

Active member
Has anyone heard of submarines during WW1/WW2 using offensive tactics as a means of defence against destroyers? I vaguely remember a report of a submarine firing a torpedo directly at a closing destroyer head on. Since depth charges had limited range, and shells would just ricochet of the top of the water, it would seem that a partly submerged submarine at periscope depth would have the first shot. Failing this it would seem relatively straightforward to design the submarine to release some mines across the destroyers path as it retreats away under battery power. Perhaps I am missing something obvious here but surely this sort of tactic may have rendered escorts redundant at a stroke?

As far as I know the direct attack was the only means available to a destroyer in the first half of the 20th Century.

The basic destroyer attack procedure was to point the ship at the target and head towards it at a moderate speed. Once the ship was generally within 1,000 yards, sufficient sonar data regarding the submarine's heading and speed should have been determined. At that point, the destroyer's helm would maneuver on a "collision course" with the target. Adjustments would be made in the DD's course to account for the approximate depth of the sub, calculating the amount of time it would take for a depth charge to sink to the lethal level. Depth charges dropped from the stern tracks would be in evenly spaced intervals. The port and starboard throwers would send DC's approximately 50 yards out on either side - forming an elongated diamond shaped pattern. The goal was to pass just far enough ahead of the submerged target and launch the DC's in the hopes that the submarine's travel would take them right into the path of the sinking ordnance.

http://www.valoratsea.com/destroyer.htm
 
Shooting head on at a destroyer only gives the U Boat caption a very small shot, a destroyer is not much more than 30 feet wide. This tactic was greatly extolled by Hollywood in many of the films about American Subs in the Pacific.
U Boat captain doing this manoeuvre would lay him self wide open to an attack with the hedgehog
 
LeEnfield

Yes, I suspected Hollywood was responsible for this idea, however the submarine would have several shots. I recall those 'depth charge' games where a submarine can release a buoyant charge that floats upwards to the surface to destoy a ship like a mine. Is this another fantasy or does it have some basis in fact? It seems relatively simple procedure for a sub to release an array of these floating mines in front of the destoyers path.
 
Very few Submarines could release mines under water, the very few submarines that carried mines carried very few torpedo's. Where as the destroyers were equipped during the war with the Hedgehog. The Hedgehog threw large mortar type bombs ahead of the destroyer in a pattern that would hit most subs. the idea was that they would only explode on contact, so if they did not hit any thing it would disturb the water and the destroyer would not lose sonar contact, so the chase could continue.
 
Well yes, the hedgehog was only deployed from 1943, before that they used conventional depth charges which had a very low success rate. However, the sort of tactic I envisage was that the submarine lays a large number of small mines between itself and the advancing destroyer to form a screen. Obviously subs would have to be adapted for this but technically it seems an obvious defense tactic. The mines could even be drawn behind the sub using cables.
 
The mine laying subs would release the old horned type mined which would be anchored to the sea the sea bed. They mainly used this type of sub on estuaries as they could slip in and out with out being seen and they stood a greater chance of hitting some thing
 
I believe there is a basic misunderstanding in this topic. Anti Destroyer warfare for the subamrine was basically avoidance. To stay hidden. The firing of a torpedo was usually the first indication that a submarine was close.

Submarines primary mission was to destroy high value targets. Those being supply, or oil tankers, or troop ships. Wasting a torpedo on a destroyer defeats the submarines mission. The destroyer wins in that scenario. Remember the mark of sucess for submarines was in the tonnage of ships they sank.

Submarines had a limited amount of weapons and would have to withdraw when these were expended.

Destroyers lose the battle when they are not able to protect the ships under their support.

Anti-submarine doctrine actually directs destroyers to maneuver to take a hit from a torpedo rather than allow it to hit a higher value target. The Captain of my ship was less than enthused about this directive. Submariners new this and could set the run depth of their torpedoes to pass under a destroyer and continue to its target.

Simple example: Destroyer's draft less than 20ft. Supply ships draft more than 20ft.

Run depth of a torpedo was always a consideration for submariners. To shallow and wave action could effect its ability's to run straight. Set to deep and it could pass under its intended target. Remember WWI and WWII torpedoes were mostly contact weapons and not guided.

Submarines always have an advantage over destroyers as they can hear a destroyer's active "pinging" at at least twice the range that it would take the destroyer to get a return from it's signal. All surface ships make considerably more noise than a submarine running submerged. Avoidance was easy.

I was a destroyer sonarman for 6 years during the early 1970's.
 
Thanks for your comments Chukpike. I'm aware that it is normal doctine to avoid detection from surface ships but I'm just trying to think out of the box here and say what would happen if the designers of submarines (in WW2 not post war) tried to introduce measures to attack the destroyers attacking them? The attack method of the destroyers in the early years was very basic, simply drop a large timed charge over the submarine and most attacks of this kind were unsuccessful.

It seems to me that there are a number of possibilities here for the submariner, either to release a spread of specialised torpedoes ones which operated near to the surface when the destroyer is nearly upon them, or to release a spread of mines which float to the surface thereby causing the destroyer to swerve. There are many more sophisticated variations on these ideas, and I except the innovative Germans must have thought about these and dismissed them.

Sorry I think more like a designer/engineer rather than an operations person who has to make do with what he has got!
 
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perseus said:
Thanks for your comments Chukpike. I'm aware that it is normal doctine to avoid detection from surface ships but I'm just trying to think out of the box here and say what would happen if the designers of submarines (in WW2 not post war) tried to introduce measures to attack the destroyers attacking them? The attack method of the destroyers in the early years was very basic, simply drop a large timed charge over the submarine and most attacks of this kind were unsuccessful.

It seems to me that there are a number of possibilities here for the submariner, either to release a spread of specialised torpedoes ones which operated near to the surface when the destroyer is nearly upon them, or to release a spread of mines which float to the surface thereby causing the destroyer to swerve. There are many more sophisticated variations on these ideas, and I except the innovative Germans must have thought about these and dismissed them.

Sorry I think more like a designer/engineer rather than an operations person who has to make do with what he has got!
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Starting in 1942, The Germans developed two Torpedoes known as TIVb Falke and the TVe (Wren). 'Falcon' and 'Gnat' in English.

These two torpedoes were specifically designed to disable Destroyers. I say disable not Destroy because they were both acoustic fish with relative slow speeds, short range, and small warheads and since they homed in on the propellers and not somewhere more vital, a hit was usually non-fatal.

The Torpedo was generally loaded in the aft tube(s) on the Type VII and Type IX. The tactics the Germans developed was to allow the target to pass behind the Uboat (usually after a depth charge Run) then fire the fish as the destroyer passed by as the acoustic sounds would be strongest and the close range gave a good chance of a hit.

This was typically used to escape a attacker as a hit usually meant the Destroyer would be dead in the water allowing the Uboat either escape or a easy target.

Changing theatres. In 1944 US Naval Intelligence figured out that over the 3 year war the Japanese had lost most for their destroyer force, so US Submarines were ordered to consider IJN Destroyers as priority targets (above Marchant ships) as they wanted to completely eliminate Japans ability to protect their Midnight Express runs.
 
mmarsh Yes, I forgot about the acoustic torpedo. Didn't the Allied ships use a decoy acoustic signature to deflect the torpedo?
 
I stand by my earlier statements. Anti destroyer warfare was avoidance. Subs would leave destroyers alone. If you prioritize all the ship types a sub would engage the last one on the list would be destroyers, right after row boats.

WWII and earlier submarines were small and had limited space for weapons. Carrying defensive weapons reduces the number of offensive weapons they could carry. Basically these subs carried around twenty torpedoes. They did not have extra space. Carrying Anti Destroyer weapons would reduce this number and their ability to carry out their primary mission. I am not saying that subs wouldn't fight a destroyer only that it would be an act of desperation.

In a way you could relate a sub to the school yard bully. They would rather pick on someone who wouldn't or couldn't fight back. Bullies don't pick on those who fight back because they could loose.

WWII subs running submerged on batteries had limited speeds and duration. They could not afford to get in a fight with a destroyer that could hang around indefinitely. Destroyers can't hear in about a thirty degree angle to the stern. To counter this destroyers turn quickly and often. A sub getting in the baffles of destroyer would have the opportunity to escape, or fire a torpedo (giving away it's position), would try and escape.

"Changing theatres. In 1944 US Naval Intelligence figured out that over the 3 year war the Japanese had lost most for their destroyer force, so US Submarines were ordered to consider IJN Destroyers as priority targets (above Marchant ships) as they wanted to completely eliminate Japans ability to protect their Midnight Express runs." quote mmarsh.

Interesting, but I would have to see the directive to believe it. As the US was fully engaged in cutting off supplies to Japan. The midnight express runs of trying to resupply the Japanese (on various islands), would still make stopping the supplies the priority.
 
Maybe this letter from Fleet Admiral King written at the end of WW ii might sum it up in regards to how he felt about submarines and the effectiveness against non-comerce type vessals.

http://www.valoratsea.com/King.htm

The first time i ever heard of the desperate act of what is reffered to as a "down the throat" shot was Cmdr Morton and USS Wahoo during its 3rd war patrol after 16 Jan 1943.. This is a partial description of the event.

"Thoroughly alerted by the white torpedo wakes scarring the surface, HARUSAME bore down on WAHOO. With nothing but mud beneath their keel, Morton ordered the periscope raised and O’Kane called out the range. Firing his last bow tube down the destroyer’s throat from 800 yards, Morton took WAHOO to 90 feet to await its short run. Most of the crew anticipated their own demise.
[FONT=Arial,Helvetica]Seconds later a devastating explosion was heard through the hull. Raising the periscope, O’Kane exclaimed that HARUSAME was broken in two and settling by the bow."[/FONT]

A down the throat works by closing to extremely short range (say 800-600 yards) and firing the torpedo (two works better) directly at the bow. Its takes the destroyer a little bit of time to realize its got one comming down the bow, as both objects (ship and torp) are closing the range quickly between each other, and sometimes the subs wake will disguise the speeding little gift coming at you. If the destroyer stays on course...one gets it in the bow. If the destroyer turns left or right...it may not turn fast enough to prevent the sides of the boat from getting hit, especially in the rear. Mortons destroyer tried to turn and got hit in the side, hence the broken in two scenario.

It was well known that the US Navy labeled all japaneese destroyers as priority targets in in 1944. One boat that took up Japanese destroyer hunting in a big way was USS Harder .Her skipper, the resolute and resourceful Commander Samuel D. Dealey, "a submariner's submariner," was posthumously awarded the Medal of Honor. In some books he took down 5 destroyers in 3 days: in others four in 3 days. even wounding a destroyer was bad, for it took it away from escort duties, and thats what you wanted: a good shot at the goodies without dying from the escorts. the thing was, he went after the escorts with this in mind: no more escorts for the frieghters, it was going to be good to get them with other subs in the areas when working as a wolf pack.

Of course, the japaneese did not have hedge hog rocket fired anti submarine charges either, so deliberatly tangling with a destroyer had a different outcome the say german sub vs US destroyer.
 
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Mark, Interesting stuff. Something else that occurs to me is if a sub could launch a spread of torpedo's say 7-8 in rapid succession. One would be directed directly at the destroyer forcing it to turn. 2 would be directed to either side but nearly head on, say at about +/- 2 degrees. 2 more would be directed at +/- 5 deg and 2 at +/- 10 degrees. The idea is as the ship turns to avoid it will expose more of its hull.

Problem is I think the torpedo tubes point in the same direction, so the sub or the torpedo's would have to be modified. In the latter case a gyro adjustment may be all that is necessary. The torpedo's would be specialist for this purpose and of course designed to run near to the water line and detonate on a glancing blow. I doubt if it would take much to sink a destroyer.
 
Down the throat shots are unique...the most you would want to throw at a vintage WWII destroyer would be 3. one aimed directly at the bow and the other 2 diverging slightly to get him in the side. if he's stupid enough to try and violently turn left or right hes toast. stays on course..he's toast.

The bad thing was, at this time of the War in the pacific, it was bad torpedos. you threw enough at one target to make up for the lousey performance. one torpedo was enough to sink a destroyer...if it went off. but you didnt take chances. a common spread was 3-4 at one target. most captains carried 24 torpedos. there were so many in the front, and so many in the back (yes fleet subs had two torpedo rooms.) you had to think of utilizing the front and rear to get the most from your load.

one trick was to lure the destroyer for a down the throat shot by running away but leaving the scope up for a reference point. sort of luring that big boy on, when you had a bad time planned for him. when he got close enough to not avoid the shot, you sent two on their way from the rear. now, you only tried this if there was only one destroyer in the vacinity. two destroyers could ruin your whole day. ;-)
 
Mark Conley said:
you only tried this if there was only one destroyer in the vacinity. two destroyers could ruin your whole day. ;-)
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Yes, but of course there must have been more situation's where the submarines outnumbered the escorts especially if the destroyers were scattered along the whole length of a convoy. I would have expected this would provide opportunities for an adjacent U boat to attack the destroyer attacking a fellow U boat.

I suppose the early U boats were essentially surface vessels that could dive, but had little manoeuvrability once reliant on their batteries underwater. The later types however were a different matter.
 
perseus said:
mmarsh Yes, I forgot about the acoustic torpedo. Didn't the Allied ships use a decoy acoustic signature to deflect the torpedo?
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The British did have a device, I forget what it was called but essentially they were noisemakers that were towed behind the destroyer to throw off acoustic torpedoes

However it was a double-edged sword because using such devices made the destroyer more easily detectable to the U-boats Hydrophones operator and could therefore announce the presence of a convoy to a Uboat, which negated a convoys biggest defense asset...to remain undetected.
 
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