His Majesty's U-Boat

Easy read about an English officer in command of a captured German U-Boat. Really well written, and easy to follow.

Steven Marshall has seen the horrors of submarine warfare first-hand. Now, he's been put in charge of a captured German U-boat, and he and his crew have a top secret mission to fulfill. The catch: his own Royal Navy comrades don't know he's one of them, and the Germans are figuring out one of their subs is behaving strangely. Marshall has no friends to rely on. More even than the usual submarine commander, he is entirely on his own.Douglas Reeman keeps finding new twists and turns to make his war-at-sea novels entertaining, and in this one, the psychological terrors of submarine warfare are magnified by the fact that sometimes it's your own Navy dropping depth bombs on you. By my count, this is Reeman's fourteenth novel, and he's definitely got his craft figured out by this point. You'll be drawn into this one.