ORIGINAL: John Lansford
Blimps were excellent coastal ASW assets; they could loiter over a spotted sub's location for hours, couldn't be detected by the sub unless it got so close to the surface it could be spotted itself, and carried plenty of ordinance. Speed wasn't a problem; at 60mph they were almost 10x faster than a submerged sub, and had a great range as well. Not so good at escorting a convoy due to weather issues, but coastal ASW patrolling was well within their capabilities.
I recall reading a great book called "Aircraft Versus Submarine 1912-1945" by Dr Alfred Pricesimilar that mentioned ASW blimps but described them as being reasonably ineffective due to their slow speed, ie little chance of sucesfully attacking a sub.
BUT just doing a google on blimp and anti submarine reveals heaps of really interesting stuff. on them.
so thanks for the heads up on this one.

