Sinking vessels in rought weather.

[Khayman]

Originally Posted by MENTAT

Why 300m ? and why not 100m?

Whats the speciality of 300m to arm itself?

Presumably 100m was not enough to ensure the safety of the sub if the torpedo went off prematurely. 300m was probably a safer number given that it's pretty pointless for a sub to blow itself up.

I think the actual German arming distance was 250 meters, but I'm not totally sure. US arming distance was 500 yards, or about 450m.

[Khayman]

If memory serves then Michael Gannon quoted above 300m as the arming distance, then later related how Hardegen closed to less than that and got a hit. He didn't explain the discrepancy in his figures. I'd have to check the book again to be sure but I'm drunk and I couldn't read a 50 foot signpost if it smacked me in the face.

[Pants]

Pistol

The device to detonate the warhead was the pistol. There were two types, magnetic and contact pistol. Most torpedoes had both types and the captain could select a combination of magnetic, contact or both, prior to launching the weapon.
The magnetic pistol was triggered by the ship’s magnetic field and was designed to explode underneath the hull. Such explosions could break a ship’s hull in two, sinking it with just one torpedo. However, magnetic pistols were prone to premature detonations, with many exploding as the torpedo approached the wake of the ship. There were several reasons for this. First, the earth’s magnetic field changes with different latitudes, which were not properly offset by the device. Second, torpedoes tend to approach the target from astern, where the differential speed was reduced. The magnetic pistol could not detect a gradual change in magnetic flux, and failed to detonate. Finally, poor design led to high vibrations within the torpedo itself, which ultimately caused the relay to fail. Until the problem was solved, the less effective contact pistol was used.
Contact pistols comprised of four whiskers mounted at the tip of the torpedo nose. They were designed to react to a glancing blow which detonated the warhead. Many problems were also encountered as it was discovered due to poor design, only a narrow impact angle of approximately 20 degrees was required to consistently trigger the pistol. There was also a safety device which armed the pistol only after a minimum run of 250 meters. For this, a small propeller was fitted to the nose of the torpedo. As it moved forward, rushing water would spin the propeller until it wound shut, arming the pistol.

Originally Posted by Pants

Pistol

The device to detonate the warhead was the pistol. There were two types, magnetic and contact pistol. Most torpedoes had both types and the captain could select a combination of magnetic, contact or both, prior to launching the weapon.

Is that true of the Germans? I've read that in US torpedoes one could not select type, and when they started to realize where the problem might lie torpedo chiefs actually had to physically remove and disable the magnetic pistol. Made for a lot of trouble.

[Pants]

Yup german torpedoes mate

[MENTAT]

Originally Posted by Khayman

Presumably 100m was not enough to ensure the safety of the sub if the torpedo went off prematurely. 300m was probably a safer number given that it's pretty pointless for a sub to blow itself up.

to blow itself up? if it goes up at 100m or 150m, will it waste its host sub? I dont think so! especially if you think Depth charges are barely effective in 50m?

Anyway aint a destroyer at 100m not more deadly?? I believe a pursuing destroyer could be hit easily with a stern torpedo as it never goes farther than a 150m perimeter in a bomb run..

I still wonder why 300m? and not 200m or 100m? That should have a better explanation than damaging the sub