Cryptonomicon

"Storm front moving in this evening. Foul weather tomorrow."

"Let's see if we can stay alive until the storm hits," Bischoff says. "Then we'll run this bucket of shit straight up the middle of the English Channel, right up Winston Churchill's fat ass, and if we die, we'll die like men."

A terrible clamor radiates through the water and pierces the hull. The men cheer sullenly; they have just sunk another ship. Whoopdy-doo!

"I think it was the destroyer," says the sound man, as if he can hardly believe their luck.

"Those homing torpedoes are bastards," Bischoff says, "when they don't turn round and home in on you."

One destroyer down, three to go. If they can sink another one, they have a chance of escaping the remaining two. But it's nearly impossible to escape from three destroyers.

"There's no time like the present," he says. "Periscope depth! Let's see what the fuck is going on, while we've got them rattled."

It is like this: one of the destroyers is sinking and another is heading towards it to render assistance. The other two are converging on where U-691 was about thirty seconds ago, but they are hindered by having to make their way through the middle of the convoy. Almost immediately, they begin to fire their guns. Bischoff looses a spread of torpedoes towards the assisting destroyer. Water is spouting up all around them now as they are straddled by shells from the other two. He does another three-sixty, fixing the image of the convoy in his mind's eye.

"Dive!" he says.

Then he has a better idea. "Belay that! Surface and go to flank speed." Any other U-boat crew would cut his throat at this moment, then surrender. But these guys don't even hesitate; either they really do love him, or they've all decided they're going to die anyway.

Twenty seconds of raw terror ensue. U-691 is screaming across the surface, banking like a Messerschmidt as shells pound into the water all around her. Crewmen are spilling out of her hatches, looking like prison camp inmates in the bright sun, trying not to slide off the deck as it tilts this way and that, diving to snap the carabiners of their safety lines onto cables before they are blown out of their shoes by the waterspouts from the exploding shells. They are manning the guns.

Then there's a big transport ship between them and the two destroyers. They're safe now, for a minute. Bischoff's up on the conning tower. He turns aft and gets a load of the other destroyer, spiraling crazily in an effort to shake off those homing torpedoes.

When they come out from behind the shelter of the big transport, Bischoff sees that his mental map of the convoy was more or less accurate. He speaks more orders to the rudder and the engines. Before the two attacking destroyers have a chance to open up with their guns again, Bischoff has got himself positioned between them and a troop transport: a decrepit ocean liner covered with a hasty coat of wartime camo. They can't shoot at him now without blowing hundreds of their own troops to shreds. But he can shoot at them. When Bischoff's men see the liner above them, and gaze across the water at the impotent destroyers, they actually break out into song: a congratulatory beer hall ditty.

U-691 is topheavy with weaponry, armed to the teeth because of the aircraft threat. Bischoffs crew opens fire on the destroyers with all of the small and medium-sized stuff, to give the deck gun crew a chance to line up its shot. At this range, the danger is that the shell will pass all the way through the destroyer's hull, and out the other side, without detonating. You have to be patient, take your time, aim for the engines. Bischoff's crew knows this.

A skull-cracking explosion sounds from the barrel of the deck gun; the shell skims the water, hits the closest destroyer right in the boilers. The destroyer doesn't blow up, but it does go dead in the water. They take a few more shots at the other destroyer and manage to knock out one of its guns and one of its depth charge launchers. Then the lookouts see airplanes headed their way, and it's time to dive. Bischoff does one final periscope scan before they go under, and is surprised to see that the destroyer that was trying to evade the torpedoes managed to do so; apparently two of them curved back and hit transport ships instead.

They go straight down to a hundred and sixty meters. Destroyers drop depth charges on them for eight hours. Bischoff takes a nap. When he wakes up, depth charges are booming all over the place and everything is fine. It should be dark and stormy up there now: bad weather for Catalinas. He evades the destroyers by (in a nutshell) doing clever things he has learned the hard way. The U-boat is as thin as a knitting needle, and when you turn it directly toward or away from the source of a ping, it makes almost no reflection. All that's required is a clear mental map of where you are with respect to the destroyers.