I hope someone can help ID this sub movie, it's really annoying me!
It was made by a British director in 1943 or 1944 i.e. while the war was ongoing. It concerned an occupied country where U-boats were being made, experimental ones. The hero of the movie was part of the workforce who were forced to help, and he was considered a traitor at first by the rest of his people.
However he was part of the crew who went out on trial of the boat - and there was a sub casting off and travelling on diesels. Not a real U-boat I imagine but it looked surprisingly close to a VIIC. He and the other workers on board hijacked it from the German crew and sailed it to England. I remember looking up the movie and hearing it was based on actual events, but I couldn't find any true instance of this happening.
He used a codename that was an old sea hero of the country he was from. Again I wish I could remember! I was going to post about it but decided not to.
The movie ends when he takes part in trials of another German U-boat and blows it up with himself onboard. This movie does exist! I just wish I could remember the name
