Hi Aaron Hamilton has a book out on von Forstner, commander of U-402 in WW2. Several times he mentions a tactic used by aircraft armed with the Mark24 FIDO acoustic torpedo. He says they carried a 500lb bomb to be dropped first on a surfaced U-boat to force it to dive. The FIDO could then be launched without being observed. It is certainly correct that it was strict doctrine for FIDO only to be used unseen. However I do not recall reading elsewhere of the specific tactic of dropping a bomb primarily to force a dive. Anyone able to confirm that?