Where's the stern tube?
 

Doing my rounds in the sub, I can never find the stern torpedo tube. I go aft past the electric motors and all that I can find is a bulkhead with a kind of desk attached to it, but no tube or torpedo in sight. Or am I just blind?

Sounds like you're in the VIIA. It had a single, external load only, rear tube that wasn't accessible from inside the sub.

The VIIB and VIIC models have the tube visible in the rear compartment, and it's worryingly open all the time!

Yeah its a shame that the rear torpedo compartment isnt animated when the torpedo is being loaded.

If you are in the VIIa, maybe you can walk aft on the deck and see the outer door. It's above the waterline.

It looks like a part is missing by looking at the GR2 file with Granny Viewer.

Oh boy, even after a couple of patches, this still ain't fixed.