Torpedo failures - weather related.

[GJO]

I am currently reading 'Iron Coffins' but have not yet reached the point in the book where Werner took his own command. In research elsewhere, I haven't found any evidence to suggest that wind speed had any effect on a torpedo's performance and although it seems logical to expect high waves to cause problems, U Boat Commanders were instructed to attack (and instructed how to attack) in these circumstances whenever a suitable target presented itself.

I agree that Hsie's work and thorough documentation is quite splendid but for my own interest I just wonder what real life evidence there is to say that a torpedo fired at close range in a big Atlantic swell would be prone to failure. Surely, the weapon was designed to be used in the Atlantic where the sea is rarely calm and huge waves are normal.

[banryu79]

Originally Posted by GJO

Surely, the weapon was designed to be used in the Atlantic where the sea is rarely calm and huge waves are normal.

Mmm... seems a logical deduction, but from experience of RL design failures (in other fields) I will not bet on it

[BigWalleye]

Originally Posted by GJO

Surely, the weapon was designed to be used in the Atlantic where the sea is rarely calm and huge waves are normal.

Based on the sorry history of poor torpedo design and development in both the German and US navies, I'm not sure that is a safe assumption.

[Lokisaga]

With these torpedoes it's important to remember that we're talking about something with the same mass as a 4-door sedan slamming into waves at 75-80 kph (45-50 mph). It stands to reason that something could be damaged and cause the torpedo to run deep, run off course, or prematurely detonate. Given how little attention the designers paid to critical components (the impact and magnetic triggers, the depth keeping machinery), I don't think strengthening the torpedo casing even occurred to them. H.sie's mood simulates a number of different mechanical failures by simply overriding the depth setting on the TDC. The torpedo runs at 25 meters and fails to detonate. It achieves the desired end result, a torpedo failure, without the need to program completely new torpedo behaviors for each possible malfunction.

[Warren Peace]

For further reading regarding the failures of German torpedoes, I would suggest this little gem:

http://digitalcommons.georgiasouther...99&context=etd

I haven't gotten through all of it yet, but thus far it has proven to be a well researched and well written thesis on the German torpedo crisis that occurred early in the war.

Given what I have read thus far regarding the depth keeping springs, heavy waves would definitely have an adverse effect on torpedo reliability. The depth keeping springs were not thoroughly tested, or reliable, to begin with; combined with the constantly changing water pressures that come with 2-3m swells, I can easily imagine some failures being the direct result of heavy waves. To bring wind speed into the equation, winds above 15kt can easily cause swells of 3m or higher.

[GJO]

Although many of us think of the breaking waves that we may see at the sea shore or in shallow water, the long rollers of the North Atlantic are quite different. Here the length of the trough between wave crests may be more than sufficient to enable a torpedo to keep to a constant depth below the surface whilst following the shape of the wave - this would be especially true if the advice provided at Torpedo School was followed regarding positioning to enable the weapon to be fired at approximately 90 degrees to the wave direction.

ETA: In heavy seas, merchant ships (especially in the days of sail or steam) would choose to head into or away from waves rather than take them broadside on. Therefore, a torpedo fired at 90 AOB would be fired along the waves rather than against them.

[BigWalleye]

Originally Posted by GJO

Although many of us think of the breaking waves that we may see at the sea shore or in shallow water, the long rollers of the North Atlantic are quite different. Here the length of the trough between wave crests may be more than sufficient to enable a torpedo to keep to a constant depth below the surface whilst following the shape of the wave - this would be especially true if the advice provided at Torpedo School was followed regarding positioning to enable the weapon to be fired at approximately 90 degrees to the wave direction.

ETA: In heavy seas, merchant ships (especially in the days of sail or steam) would choose to head into or away from waves rather than take them broadside on. Therefore, a torpedo fired at 90 AOB would be fired along the waves rather than against them.

"...along the waves..." doesn't mean that they would be tucked safely in the belly of the wave. A torpedo is not a bullet. It takes 30-120 seconds to reach its target. During that time, the torpedo is going to be passed over by several swells and troughs. Amd, at 15 m/s wind speed, those are not going to be long, gentle rollers. There are going to be perturbing forces on the torpedo which are going to push it in different directions over time. Think of trying to hold a boat on course in beam winds and seas. Granted that the torpedo is below the surface, but the water within a wave height of the surface is moving in a churning circular flow pattern. And the torpedo is steered by a mechanical feedback loop that is prone to upset by impulsive inputs.

Again, it is your game and you are free to play it in any way that you enjoy. So turn off h.sie's Torpedo Failure Fix and go out and sink 'em in a howling gale. We all adjust the game to make it play the way we want. Personally, I object to the lack of crew assistance and am willing to accept some totally unrealistic compromises to avoid having to do things no R/L sub skipper ever had to do. YMMV

BTW, how do you line up a shot? Do you turn off No Stabilized View? Either on the surface or at periscope depth in 15 m/s met conditions, the sub is liable to be moving around pretty well, maybe even broaching, and the peri or UZO under water much of the time. I can't even line up a shot under those conditions. What's your technique?

[GJO]

My technique is to get in real close (between 250 and 450 metres) on a parallel course matching the targets speed then drop back very slightly and fire with a 90 degree giro angle. The torpedo usually explodes amidships on the target which is often enough to break it's back or at least put it's engine room out of action. My only problem is that I sometime get port and starboard mixed up and have been known to send one off in entirely the wrong direction!

[Iron Budokan]

Originally Posted by GJO

Although many of us think of the breaking waves that we may see at the sea shore or in shallow water, the long rollers of the North Atlantic are quite different. Here the length of the trough between wave crests may be more than sufficient to enable a torpedo to keep to a constant depth below the surface whilst following the shape of the wave - this would be especially true if the advice provided at Torpedo School was followed regarding positioning to enable the weapon to be fired at approximately 90 degrees to the wave direction.

ETA: In heavy seas, merchant ships (especially in the days of sail or steam) would choose to head into or away from waves rather than take them broadside on. Therefore, a torpedo fired at 90 AOB would be fired along the waves rather than against them.

This is interesting information, thank you!

[Warren Peace]

Originally Posted by BL!TZKR!EG

I just added this to my list of documents on the server. Have you got more?

As of this point, no, at least none that haven't already been mentioned and/or discussed to death in previous threads. If I happen across any more gems, I'll be certain to bring them to the community's attention.

I'm glad you all have been enjoying that thesis as much as I did, it really is a great insight into what kind of crap the Kaleuns had to deal with during the early years (I feel especially bad for Zahn. A type II having a perfect shot on the Nelson, only to be screwed because of faulty torpedoes, small surprise he was mentally broken for awhile).