My WAC war diary
 

Patrol 6:

Departed Wilhelmshaven on March 22, 1940. The war with Norway and Denmark is imminent. Bdu sent us (U-45) to a grid near Trondheim in preparation for German invasion. After a week of dull patrol (not been able to spot any worthy target), Wolfgang my 1st WO spot a sub at 11000 meters. It turned out to be a U-Class British sub patrolling in my grid. After observing it at a long range and taking its bearings, I was able to figure out its rough position and course. I was in a pretty tough position being miles away from behind. Using the calculated course, I was able to get ahead of it and laid an ambush. The sun is coming up and the sub is traveling at 11kts. Time is of essence to set up the shot. There is no target info in the manual, so I had to rely on experience to figure AOB and range. At 10:12, "torpedo los". The first electric torp went too deep, passing right underneath the sub. The 2nd steam torpedo, missed by about an inch. The British by now has spotted my torpedo's wake and starts to dive. I quickly got off a third shot. The fish hits the sub near the electric engine room. However, the sub refuses to go down. I don't have a good angle any more, so I surfaced to sink it with deck gun. But the Brit fights back. After a few minutes of gun duel, the sub finally went down. It's only a 800ton kill but well worth it. If I don't sink it, I might become the hunted by this deadly opponent. :D