Just for the record:

U-429, a Type VIIC, had no combat patrols or kills to its credit (info this site)

The USS Swordfish (SS-193) sank 12 ships on 13 combat patrols, and was lost 1/12/45 (JANAC records, from [www.fleetsubmarine.com]) possibly due to a mine off of Okinawa.

So, this movie is not literal history. But that doesn't mean it can't be a good movie, and a good sub movie. Many electrons are spilt complaining about inaccurate Hollywood, well, here is our chance to make a difference! Let's help this guy out!

To Ken Sargent:
In case you may not know, while this site has some truly world class experts on U-boat history and technical details, many here may be a bit sensitive regarding a Hollywood U-boat movie after the laughably historically inaccurate U-571. So be understanding.

What I would suggest as a first cut is to search the phorum postings in both the general and technical forums for the issues you speak of - a lot of these subjects have been discussed in the past, and the search engine is pretty good. Some answers are probably already here. You'll quickly see who the knowledgeable posters are, and they often leave live e-mail addresses - I suspect most will be glad to help. Shouldn't take more than a bit to find them.

Also, have you read 'Neither Sharks nor Wolves, the Men of Hitler's U-boat Arm", by Timothy Mulligan? He details the types of people who both commanded and served on a U-boat. This would be helpful in casting extras, and characterizing the German crew.

For example, did you know that many U-boat men were from the skilled metal working trades, and most were Protestants from Northern Germany? A total opposite to the political Bavarians that dominated, say, the SS. That the German Navy, and the U-boat arm in particular, were carefully apolitical - with party activity and membership discouraged?

Mulligan himself might help you - he works at NARA, I believe.