Late spring 1940 after my commissioning U-99, a VII-B class boat, I remember Prien in U-47 returning furiously from the Norwegian campaign. He had fired all his torpedoes at British troop transports at anchor without any result 'though they were sure targets through overlapping. This experience was nothing new to me, as during the first half year of the war I had got used to the fact that our magnetic fused torpedoes were highly unreliable. If they detonated at all it might be prematurely or behind the target but not correctly underneath its center keel plate.

The torpedo personnel on board had to be very strict in frequently adjusting the war heads according to the geographical latitude because the fuse worked with the inclination of the magnetic needle - i.e. by the change of the magnetic field by the target. But in the meantime the Royal Navy had installed the antidote suggested by the German traitor in his early war letter to the British Naval Attaché at Oslo, known as the Oslo Report, namely degaussing.

During that time I had another experience with our HAPPY TIME torpedoes. Part of the training of the new crew was two weeks of torpedo practice. Even at the beginning, when course and speed of the target were known, the day torpedoes missed behind and the night torpedoes showed by the lighting of the side of the target where the torpedo passed underneath, namely about the center.

To me this was a sure sign that the steering mechanism of the torpedo was correct, but that the observers on the target ship were not able to see exactly where the head of the bubble track crossed the wake of the ship. From that point, they had to give allowance for the time for the time of the rising of the exhaust bubbles from the set depth of the torpedo.

I sent my Second Lieutnant, the gunner, there in order to establish beyond doubt whether the observations were correct.

His report: Yes. The Commander of the training squadron, Cdr Hashagen, a WW I submarine ace, said he would request a prolongation of my training time with his establishment, although my earlier successes with U-23 had shown that I had been able to sink ships somehow.

My argument that everything was a case of his rotten torpedoes, which were not able to run at the set depth, did not convince him who came from the First Class Imperial Navy where such drawbacks had been unimaginable. To avoid any more or less dishonorable prolongation for a submarine captain decorated with the IRON CROSS FIRST CLASS, I decided to show him that I was able to hit targets also during daylight. Therefore I always aimed at a point before the bow of the target ship and thus obtained the very best results which, after all, convinced Hashagen of my capabilities.

(continued in KTB #111)