Evacuees and the causes for German naval attacks on civilian ships during World War II
Miracles on the Water: The Heroic Survivors of a World War II U-Boat Attack
...At noon that day, Heinrich Bleichrodt was at the conning tower of U-48. Swells rose high, and it was difficult to see, but through his attack periscope Bleichrodt could make out a few distinct, slow-moving vessels. Drawing nearer, he found more ships. Bleichrodt watched for a while, then ordered his crew to swing a wide circle around the scene. From his perch he was soon able to estimate the size, position, and speed of his target.
Here was a sizable convoy, much larger than the one he had discovered and attacked three days before off the Irish coast. These ships were sailing westward, in a slight zigzag pattern, at no more than seven or eight knots. And there were at least a dozen of them, fat targets on the choppy water.
Bleichrodt trained his eye on the convoy's center position, and the broad outline of what appeared to be its lead vessel. That's a big one, he thought. Probably a passenger liner. Concentrating his focus, Bleichrodt could see guns mounted on the liner's deck.
Heinrich Bleichrodt conferred with his officers. It was an inviting target to be sure, almost too easy, were it not for the turbulent seas. They were puzzled by one thing, one critical element missing from what they had seen through the periscope: Where was the escort vessel?
U-48's men had never seen such an impressive collection of vessels sailing naked, as it were, without some cover from the Royal Navy. Rolf Hilse, one of the submarine's wireless operators and keeper of Bleichrodt's logbook, wondered whether the was something different about this particular group of ships. There is no escort, Hilse said to himself. She is sailing alone. The sight of the convoy broke the day's monotony and piqued curiosity on board U-48. "It makes no sense," Hisle told a few crewman.
Ajax wasn't sure what do make of it either, but he chose not to dwell on the question. Heinrich Bleichrodt harbored no doubt about one thing: The ship was a legitimate target. She was sailing in convoy, she was armed, she was clearly the convoy's prize, long and tall and perched as she was at the lead. To Bleichrodt the missing naval escort was a curiosity – nothing more...
So the discussion on board U-48 settled quickly on what sort of attack, and when. When to fire the torpedoes? U-boat commanders could elect to attack from above or below the surface, depending on the prevalent conditions... For the moment, the seas were too rough for an underwater attack, and visibility still good enough to make surface strike dangerous. U-48 might be seen and herself become a target; the City of Benares had guns that could reach Bleichrodt's position. And rough seas could throw off a torpedo's trajectory. In any event, Bleichrodt reflected, there was no reason to rush. So Ajax set a west-southwesterly course, pulling U-48 past the City of Benares, and he waited for calm. And for night. (p. 62)