The problem is if any torpedoes turn out to be a dud, he runs the risk of not being able to sink anything. If the two torpedoes miss (or one of them at least), or detonate prematurely, then at least one more torpedo needs to be launched. Problem is that the BB might be alerted to his presence by then, and would likely speed up/begin evasive maneuvers (unless it has depth charges).

Its tough to let tonnage go, but I think he made the right choice.

Thanks guys for the support and opinions.

I dont think there's right or wrong decision here. You just have to go by the situation at hand. I would have probably engaged the BB if I had been able to get any closer.
With 4 torpedoes and noway to get closer than 6500m of the BB I thought I had a better chance to sink the tankers.
And since this would have not been my first BB sunk it was easier to let it go.

Where are those big aircraft carriers? :arrgh!:

Anyway the crew is happy that we're heading home and most importantly everyone's still alive and well

Part of your decision/view is based on your own perceptions/goals in the war. To be more like a true u-boat kaleun you'd go for the tankers. Had I been in that same situation (at that point in actual history) the BB would feel to be the better target.

Germany didn't have much of a surface fleet to begin with, and with all the English capital ships and cruisers made it very hard for them to operate. If you go after warships (except DD's) and reduce their ability wage war to me seems like a more valuable return. Big warships are expensive and difficult to replace. With the larger German warships like the Bismark being able to move out into the Atlantic without having to worry so much about a fleet of a dozen+ ships that could come chasing after her and instead there were only 4 available Capital ships the odds shift dramatically. First you remove the English surface fleet will allow the warships to go after convoys, and instead of having to dodge the escorts they'd easily be outmatched by the BB. 1 BB could've sank an entire convoy, cruised around looking for more till fuel or ammo ran low.

BBs can go down with surprisingly few torps, but I play GWX so perhaps the sinking mechanic helps quite a lot :yep:. I once came across HMS Ramillies in a convoy and managed to get a hit on her bow, and another lucky hit right on her stern. She listed and after about half and hour went to the bottom.

A really important thing is to spread the torps along the length of the ship and not try to hit the same spot unless you know for sure it's a critical hit area (like under the turrets). I find fore and aft are good points to attack and can get you surprising tonnage even with one fish on big merchants after some time to allow for sinking :arrgh!: