Since this thread is hopelessly off-topic I'll add that I toured U-995 in Kiel, Germany many years ago. The interior was like a sardine can and at 6'3" I almost had to crawl through it. The bunks couldn't have been more than 15" from the ones above and below. I couldn't imagine being at sea or in battle in that thing. No place for anyone with claustrophobia.
By the way, one of my favorite movies is U-571. Highly recommended for submarine warfare fans.