Well, it was night with very choppy seas in my patrol area and had a small merchant running away (she hadn't noticed me though...so moving on a straight course). I was directly behind her following in her wake. She was steaming at probably full speed which is 11 knots, same as my Type II. So I was gaining on her very very slowly...about a 100 metres per km. So it was either go for a long shot or forget about her.
So I fired all my 3 torps. First one was from about 600 metres. I set it on medium speed, impact and the same depth under keel as the target...it missed and exploded way way in front of the target. The second one was set at magnetic, fast speed and I left keel depth the same. This one missed and was never heard from again. The third torp was set at magnetic, medium speed and the keel depth adjusted to a metre and a half above the targets keel depth. This is the result:
I have no idea if it hit the ship or detonated underneath it...I would guess the latter. The ship went on for about a km before it started taking a lot of water from the rear. It then exploded and broke in two...all hands lost.
I think it was more luck than anything on my part....first time I have ever succeeded with a stern shot
edit: Just thought about it....it did detonate the magnetic pistol under her because the ship's prop was undamaged considering it kept steaming. If it impacted her stern, her prop would've been gone. Makes sense. I set all the torps depth wrong and shallower than I wanted because I identified the ship wrong and thought it had a shallower draft...I only noticed that afterwards, but it worked. Did I learn anything from this? No.