I'm pretty sure it's already posted somewhere, but just to make sure everyone knows about this:
https://www.hnsa.org/manuals-documents/
At the bottom of the page, under a wealth of other tactical and technical information you can find
all submarine war patrol reports of US WWII submarines.
Other sites make you pay, this one offers it for everyone to read at no cost.
These war patrol reports are the equivalent of the Kriegstagebücher for German WWII submarines. They offer a lot of insight into the tactics, challenges (there were many) and psychology of the crew and officers involved.