Magnetic exploder questions

[maillemaker]

What was it about the fjords that caused a magnetic field disruption?

Steve

[Jimbuna]

Originally Posted by maillemaker

What was it about the fjords that caused a magnetic field disruption?

Steve

The magnetic detonator anomoly:

The magnetic detonator however proved to be immune to simple fixes. It was supposed to detonate when it passed underneath a ship’s keel, as it was triggered by a sudden change in magnetic fields. This did not work as intended as the British had found a way to reduce a ship’s magnetic field by degaussing. Additionally, the earth’s magnetic fields also varied at different geographical locations and were influenced by iron ore deposits beneath the sea bed. Only when the completely redesigned Pi2 detonator had been introduced in December 1942, the problems of magnetic detonator continued to plague the U-boat Force.
But even if the detonators had been working flawlessly, problems with depth keeping meant that torpedoes were running two to three meters too deep. The depth keeping device worked by using an atmospheric chamber which controlled running depth. The Torpedo Directorate conducted new tests and could not discover any flaws. This occurred because the test torpedoes were launched from normal atmospheric conditions. But since atmospheric pressure inside a U-boat varied greatly, especially after prolonged submerged activity, air would leak into the torpedo chamber, effectively recalibrating the depth sensor.

[maillemaker]

So is Norway heavy in iron ore or something?

Steve

[Jimbuna]

Norway just happened to be the area where most prize targets were on offer and missed/lost....it was more down to atmospheric pressure conditions.

[TorpX]

Perhaps it's not the last word on German torpedos, but this is what Frederick J. Milford had to say on the subject:

Exactly this problem affected the magnetic exploders developed by the Royal Navy, the German navy and the US Navy. The Royal Navy quickly abandoned magnetic influence devices and relied on contact exploders. The German navy provided a sensitivity adjustment that would, in principle, compensate for changes in latitude. This was unsatisfactory and it too was abandoned fairly quickly12. The BuOrd/Naval Torpedo Station Newport response was first denial that there was a problem, then a complicated set of instructions for setting the exploders for different latitudes.

Does anyone know for sure if Germany was still using magnetic pistols late in the war?

[Sailor Steve]

Yes, they came up with a new, more reliable version in December 1942, and after that had few problems.

[Jimbuna]

Not sure if Steve would agree with me but the Americans had possibly more trouble with their detonators and despite numerous complaints eventually resorted to firing them at a cliff face then sending divers down to recover them for examination.

I know they lost a lot more potential heavy warship tonnage (Japanese) than the Germans ever did (Royal Navy).