This is all probably to do with the level of crew experience in the warships. I tried surfacing on the Mogami in the Torpedo School lesson and the results were disappointing for the Japanese

Looked like the gunners were all drunk!
I then edited the MIS file and gave the Mogami an 'elite' crew. This time when I surfaced the gunnery was deadly accurate and I didn't last very long!
There is definitely something wrong, but it should be a fairly easy fix...though changing the crew skill level of every randomly generated ship in the campaign might not be so easy!