On this Day in the Battle of the Atlantic...

...U-30, a Type VIIA boat, sank the British liner Athenae. Kapitanlieutenant Fritz-Julius Lemp would go on to sink 19 more ships for a total of just short of 100000 tonnes. In December 1939 Lemp recorded a hit on HMS Barham, but failed to sink the battleship. Lemp died on May 9, 1941, while commanding U-110. U-110 was captured by the British and looted of its Enigma machines and other equipment before being scuttled. U-30 survived the greater portion of the Battle of the Atlantic, and was scuttled shortly before the war ended.

Lemp's tonnage total makes him a second order U-boat "ace"; 34 U-boat commanders sank 100000+ tonnes, while another 49 sank 50000+, not including warships. As is the case with aerial combat, the top performers account for an inordinately large percentage of total destroyed tonnage during the war. Commander aggressiveness and competence were among the most important variables dictating success. The same would apply in the Pacific, where pre-war, tentative submarine commanders would eventually be replaced by a far more aggressive generation. In fairness to the early USN commanders, however, the early unreliability of American torpedoes and the expectation that submarines would operate against heavily defended fleet targets, rather than against commercial targets, weighed against aggressive tactical employment.