The Fritz-X had timers on it to detonate some many seconds after bomb stopped. At Salerno, Warspite was attacked by 3 bombs, 2 were near misses and 1 struck the ship, plunged through 6 decks and blew a hole out the bottom of the ship. Oh they also all hit within seconds of each other.

Also, Imagine subs in Late 1942 with 30 to 40 miles radar coverage for hunting and full deployment on subs instead of late 1944 and limited deployment of the Berlin sets as well. No need to deploy the Bachstelze.

Russ / Roller007