Gents,
Currently I'm reading this book:
http://www.stephenlmoore.com/sm_lost.html
It is excellent and fully describes first hand what submariners endured in the POW camps. It was not pleasant. Not at all. Reading some of the accounts by the men that were there gets me a bit angered. At any rate, I recommend this book as a must read if the silent service during WW2 intrigues you. Fear not the price. Amazon has it for under $20.00 used and if you collect WW2 submarine books for your library this is a must have.
Carry on!