Whale factory Ship?
 

During my fifth patrol (new career) I encounter a ASW Trawler followed by a 'Whale Factory Ship' on a Westward course NW of the Hebridean Island of Tiree. I surfaced and put two torpedoes into the 'Whale Factory Ship' before the ASW Trawler turned about to engage me with gunfire. With the sea unusually calm, I was able to return fire but took some damage - the fight went on for some time until the ASW Trawler turned away having sustained several hits - I was unable to make enough speed to pursue (engine damage) so submerged while the damage team went about their repairs. The 'Whale Factory Ship' had disappeared completely and looking at the chart I could see a nice red 'wreck' mark where I had attacked it but there was nothing on my 'Captain's Log' except ships that had been sunk earlier in the patrol. I am just wondering why this very obvious sinking had not been recorded?

I'm not sure. Even sinking a neutral or friendly ship should show up in the patrol log.

I'm sorry to derail in the very first reply, but you do bring up another beef I have with the game:
Any shell hit that could damage your engines would also leave a hole in the pressure hull. You should not have been able to dive at all, for the rest of the patrol.

Maybe the Trawler scored the last hit on the ship and gets some negative renown when back in homeport, for sinking one of his own?

I agree - the Diesel engines and their immediate shafts are contained in the pressure hull but a shell exploding close by could possibly cause a shock sufficient to render catastrophic damage without penetrating the hull - Examples could include an uncontrolled inrush of sea water through a damaged air intake. Nevertheless for an engine to be destroyed you would normally expect there to have been a breach of the pressure hull such that diving would not be possible.

A very likely possibility - I had positioned myself so that the target was partially protecting me from the trawler. I hadn't realised that, in the game, if the last shot came from elsewhere, I might lose the credit for the kill and consequently the renown points.

^ ^ ^

Something I had not thought of. It is indeed a possibility that the target was sunk by one of his own. :sunny:

I have had it happen in convoys where I surfaced in the center, early war, and the escorts attempt to fire on me but their charges are in between me and the escort it is quite fun having them sink their own ships.

As for the shell damaging your diesels IRL that is the ultamite screwed because the PH would have been torn open by a HE shell to the point where a storm would cause some havok.

It has just happened again but this time I got credited with the sinking of the 12,000+ ton Whale Factory Ship but was not credited with its accompanying Large Cargo ship that I believe I sank also. It happened like this:

I was patrolling submerged about two hundred miles West of the Scilly Isles when the hydrophone operator reported a Merchant travelling slowly on a closing course - it was late on a January afternoon with the sea unusually calm. I set a course to position myself for an attack and, as the range closed to 450 Metres, I put two torpedoes into the ship which I had identified as a Large Cargo flying the Red Ensign at the same time I noted another ship following closely and this turned out to be the Whale Factory Ship - I put two torpedoes into that too and despite a slightly unfavourable angle both exploded and the Whale Factory Ship slowed until stationary. In the meantime my crew were busy reloading with my last torpedo and my batteries were down to 10% so I took the decision to surface - the Cargo ship was still underway and although not obviously armed, it positioned itself between the Whale Factory Ship and my boat and engaged me with machine gun fire which forced me to submerge again - even then, machine gun fire was occasionally hitting the periscope (no damage incurred) so I retracted it until my last torpedo was ready to fire. At last I was ready to fire so I raised the periscope again and could see the Whale Factory Ship still afloat and still stationary. There was no sign of the Large Cargo but there was evidence that it had sunk (I have the debris and lifeboats mod enabled - and all of this was there on the surface together with an oil patch) but there was no wreck icon on the chart and no mention in the log. Fortunately my last torpedo finished the Whale Factory Ship and it's sinking was marked on the chart and credited in my log. I just wonder what happened to the Large Cargo - one possibility is that it collided with my boat while I was diving because a short time after I had lowered my periscope, there was a nasty scraping noise and my conning tower suffered damage with H. I. Reduced to 97% - then again the damage may have been caused by the machine gun fire after I had lowered the periscope while still only just below the surface - and the noises may have been from the ship sinking.