It is certainly a crap of a film! The only interesting stuuf are the bloody effects! I love the U-boats metal twisting and twirling like paper...

And the bloody depth charges, WOW!

But the script, the story, the suspense, the historical accuracy, the performance of the actors: CRAP!
Wouldn't it have been better if they would have been attacked by a British aeroplane or destroyer? It was far more plausible...