Question about cameras on Uboats
 

How often were photo cameras brought on uboats? And if they were brought, was the film developed on board the boat or after the patrol was over?

Thanks.

Mostly discouraged for security reasons-same with private diaries.
If a correspondent was on board-different story.

Did the captain's keep a diary other than the patrol log?

And do you think the film was developed on the boat?

Probably not on both questions. The Captain was most responsible for following orders\instructions.
A u boat doesn't have room for a dark room, nor would they want to store chemicals.