Dear,

Sorry for Gasaway's narrative but U64 did not fire any torpedoes on April 10, 1940 (neither did she see 2 cruisers). See her KTB, both the original German version or the (correctly) translated online version pointed out by Thorsten. KTB U64 explains why U64 did not fire torpedoes at the destroyers.

The explosions mentioned were NOT from prematurely exploding torpedoes but from depth charges of the destroyers HMS HAVOCK and HMS GREYHOUND attacking the u-boat they had spotted. See TNA ADM199/1974.

Regards,
Walter