ok, got the problem figured out. No wonder why the devs took the dynamic shadows out. They are a pain to setup correctly
here shows the shadows in the interior of the Turm and the shadow cast on the hull of sub (it's not broken!)
and check out this beautiful Turm shadow with the railing and all showing
Now to add my flags and pennants to it and see if they are shadowed (by all accounts they should be). I just might have to start playing SH3 again....