U-123 off the American Coast

Reinhard Hardegen commands U-123, one of the few long-range Type IX submarines that Admiral Karl Dönitz has unleashed against American shipping in the wake of the United States entering the war. Setting out from the Breton bases, he has crossed the Atlantic to reach, in early January, the busy waters between New York and Cape Hatteras.

What he finds exceeds the Kriegsmarine's hopes. The coast observes neither blackout nor organised convoys: lighthouses turn, buoys blink, the cities' signs blaze through the night. Freighters and tankers stand out in sharp silhouette against that glow, offered up as if on exercise. But U-123 carries only a limited number of torpedoes, and every day spent at such shallow depth exposes her to a patrol or to an aircraft rising from the nearby shore.

Hardegen must decide how to make the most of this windfall. He can attack on the surface at night, combining deck gun and torpedoes to sink the maximum tonnage while the coast stays blind; instead reserve his torpedoes for the largest tankers and conserve his ammunition; or play it safe, diving and slipping away as soon as an escort or aircraft draws near, even at the cost of letting prey escape.