Historical torpedo fusing

[andqui]

I'm finding lots of contradictory information about this. What types of detonators were available for different torpedoes at different times.

For example, this is what I have been able to find:
G7a T1: Impact and magnetic (both reliable)
G7e T2: Impact and magnetic (magnetic very unreliable, after Norway impact only shots ordered. Impact also somewhat unreliable)
G7e T3: Impact and magnetic (both reliable, all torpedos after this feature reliable detonators)

Is this information accurate. One source said that the G7a only had contact detonators. If they also had magnetic, were they of the same type as the T2 (i.e. very unreliable?) Was the G7a's contact detonator also unreliable, or did it and the T2 use different versions?

Last, does GWX or any other mod accurately simulate the failure rates- I ask because I'm playing in late 1939 and early 1940 at the moment and have noticed no duds or prematures or other failures.

thanks

[Jimbuna]

Enable realistic torpedoes in the options menu.

[sublynx]

The war diary Dönitz kept during the war is published on the internet at the address: http://www.uboatarchive.net/BDUKTB.htm

The introductory text to the diary says that "A selection of the wide range of topics mentioned in the KTB includes: torpedo failures and developments (PG's 30248, 30250-30251, 30256, 30262, 30264, 30304b, 30323, 30332, 30339, 30350)"


I think you could read those diaries and get a reliable picture of the torpedo failures. Different books seem to have contradictory opinions, so the diary is probably the best way to get a more objective view on this.

If you have torpedo failures on, you should get duds in GWX. Are you always shooting close to an AOB of 90 degrees and gyro angle close to 0? If so, there would be a lot less failures. Historically speaking the torpedoes should have worked ok, even if shot from a bad angle or AOB - but they didn't. And if I shoot a torpedo from less than perfect solution, I do get torpedo failures. Not as frequently as the U-boats really had, but often enough to make me wanna punch those responsible

[andqui]

I am using the realistic torpedo option- but I don't think I've shot from over 1000 meters or had an impact angle less than 75 degrees, so maybe it's me not letting me have duds.

In 30256, Doenitz claims that 40% of missed shots can be accounted for due to torpedo failure- and I have had several instances when I was sure my firing data was correct and only saw one hit, so it seems as if that is behaving realistically. I play with external and event camera off, so it's a bit hard to verify if a torpedo has failed to explode or simply missed. However, out of 20 torpedoes I have fired in this career, around a third of them have been with magnetic fuses, and none have detonated prematurely, which I understand was the main problem with the early war magnetic fuse.

Any word on weather or not the G7a was equipped with a magnetic fuse, and was that fuse was more reliable than the one on the TII?

[sublynx]

Originally Posted by andqui

I play with external and event camera off, so it's a bit hard to verify if a torpedo has failed to explode or simply missed. However, out of 20 torpedoes I have fired in this career, around a third of them have been with magnetic fuses, and none have detonated prematurely, which I understand was the main problem with the early war magnetic fuse.

Any word on weather or not the G7a was equipped with a magnetic fuse, and was that fuse was more reliable than the one on the TII?

Failure to explode can be verified if you listen to the torpedo with the hydrophone when it is approaching the ship. You will hear a metallic thud and not a Ka-Boom if it hits, but doesn't detonate. I don't know how to verify in 100 % difficulty if the game simulates depth keeping problems. Maybe shoot two torpedoes to the same point as quickly as you can. If the other hits and explodes and the other does not hit nor make that thud sound, then it maybe went under the ship, I don't know.

I have had premature detonations but only seldom. That problem is worse, if I shoot torpedoes in heavy seas and if I use a G7a with a speed setting of 44 knots. I haven't used a speed of 44 knots in a long time now, though, because I understand that, that speed setting was actually not used with submarine launched torpedoes.

Gordon Williamson's book The Story of the U-boat in World War II claims that G7a's were equipped with an impact detonator but the book also claims that G7a's range was 6000 meters, so I don't think it's very reliable. From what I remember reading elsewhere and from BdU's KTB I think it's very probable that G7a's were actually using the same detonator as G7e. But that's only a hunch.

[Missing Name]

Originally Posted by andqui

Last, does GWX or any other mod accurately simulate the failure rates- I ask because I'm playing in late 1939 and early 1940 at the moment and have noticed no duds or prematures or other failures.

Consider yourself lucky. I had 4 perfect impact shots set up on a VERY large, slow moving target. All clanged off the side, no more than 5* off 90*.

TI G7A & TII G7E used the same pistols.

[Jimbuna]

There may be something of use on the topic here:

http://www.navweaps.com/

[Obltn Strand]

http://www.uboatarchive.net/KTBNotesArmament.htm

[Sailor Steve]

That link (I was familiar with the site but not that particular document) had an interesting point:

Pi 2 (Pi 39H)

December 1942

Selectable impact and magnetic or impact alone (new German designed magnetic detonator - impact mechanism same as Pi1) G7e TIII

That got my attention, and a quick search led me to this incredible find.
http://eaglescholar.georgiasouthern...._201005_MA.pdf

Here is the information I've been looking for for years. The whole file is worth downloading and reading in depth, but here is the relevant information.

At the time U-boats carried torpedoes equipped with either the MZ or AZ pistol. The option that would later allow the commander to interchange these settings while on patrol had not yet come into being, so whatever setting the pistol was set to when delivered to the boat was what it was stuck with for the duration of the patrol. It was impossible, in other words, for a commander to change his torpedo's pistols from MZ to AZ setting and vice-versa.

Page 47.



Things I've learned from this single document:

1. The date of the order to stop using MZ (magnetic) pistols, and the beginning of the "Happy Times" - June 1, 1940 (page 132).

2. The date of the introduction of the new improved MZ pistol - November 1942 (Mediterranean) and December 1942 (Atlantic). (page 155)

3. Apparently I've been wrong and SH3 had it right, at least starting in 1943. From that point on there was indeed a selector switch. (Obltn Strand's link, as quoted above).

This is the biggest find in a long time, to my mind anyway.

[FUBAR295]

Nice find SS

Thamks, Steve.

[Jimbuna]

Good catch mate

[sublynx]

Absolutely marvelous!!!

Thanks, Strand for the major find there and Steve for the follow-up job

I am your humble slave and devotee as of this day

Helvetin hyvä löytö Strand!!!