Heh. My last cruise, I surfaced after a target missed my torpedos (not the other way around, mind you). I didn't see any guns from my 'scope, so I figured I was ok. My crew starting plinking away at 'em with the deck gun (under my guidance). We aimed for the waterline, right under the stack, hoping to fill the engine room so she'd stop. Stopped ships make for good targets.
Yeah, well... apparently I aim my fish like I search a target for guns. There were two... one on the port side of the bow, the other on the starboard side of the stern. Of course, I surfaced on the port side of the stern, so they couldn't hit me.
Until I maneuvered within range of the bow gun. It wasn't a deck gun, putting holes in my boat. More of an antiaircraft caliber. I stayed surfaced, mainly 'cause the merchant crew couldn't aim. They fired off wildly, as I continued to pump deck gun rounds into them, while heeling over to stay out of their firing arc.
Needless to say, it didn't work. One of their last attempts went straight into the deck gun position. The tracers were straight into the deck gun view... they looked huge. The target's gun stopped firing, and I breathed a sigh of relief. Then the "man down on the deck!" calls started coming in.
I had moved my entire aft torpedo room crew up to the deck gun. Lost 'em all. All of 'em dead. Six men died because I couldn't bother to dive. The boat didn't incure any other damage, and nobody else was lost.
It made me think... by all rights, that's six letters that I should have to sit down and write, explaining their deaths in a flowery language promoting their service, knowing deep inside that I could've saved 'em simply by diving, instead of trying to maneuver on the surface. Thank God this is just a bunch of electrons streaming around in a couple boxes

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All of the above was running RFB, btw.