The Secret Weapon (J.E. Macdonnell's Royal Australian Navy World War II Fiction, #14)

Royal Australian Navy Commander Bentley knew this was the time for nothing but concentrated attack … This was no exercise, no leisure manoeuvre by which Wind Rode could show her competence. They were up against a desperate enemy submarine, a vehicle armed with explosive teeth and claws—the destructive potential of which they could not gauge. A terrifying secret weapon!