Picture the scene, we're on the bridge of HMS Happless, a Royal Navy destroyer somewhere in the North Atlantic. It's November 18th 1942, the middle of winter, we're steaming into the teeth of a force nine gale which is howling in from the North East. Huge mountainous grey, green waves are crashing down on the deck, obscuring the forward gun turret. Strung out ahead of us are the running lights of the convoy of ships carrying vital supplies from our allies across the Atlantic. It's our job to protect them from the wolves of the sea: the dreaded Nazi U-boats that strike from the ocean's icy depths without warning; sending men, equipment and supplies to Davy Jones' locker. Suddenly, the wind drops, the clouds part, the maelstrom calms. The captain lights his pipe and takes a swig from his cocoa: the sweet smell of tobacco and chocolate wafts across the small open space of the bridge. He pulls the hood of his duffel coat tighter against the biting cold. He looks at us and almost whispers, "Jerry's quiet tonight chaps … damned quiet… too damned quiet …" It is the calm before the storm: we eye the surrounding waters for the tell tale sign of a periscope, we know that it is a case of when, not if…