How bad were things? American forces had been raised to Defcon 3, their highest ever. Soviet naval and civilian vessels were about to be blockaded from Cuba by the US Navy. Nikita Krushchev and Fidel Castro were rattling sabres. President John Kennedy, in Washington, was not about to back down.
While politicians dithered in Ottawa, Dyer quietly prepared for the worst. On his own initiative he set in motion the dispersal of his naval forces from their home base in Halifax, and those already at sea were recalled.
The RCN was primarily an anti-submarine force, with Tracker aircraft on board HMCS Bonaventure, squadrons of destroyers, frigates, and...submarines! Not officially, of course, because the submarines at Admiral Dyer's beck and call were British. A-boats, in fact. They belonged to the Sixth Submarine Squadron, based in Halifax and partly manned by Canadians.
One of them, HMS Alderney, was already at sea. She had stored for a "war patrol" on the night of the 22nd, and sailed on the 23rd for the North Atlantic. Joined later by sister boat HMS Astute, she would take up station two hundred miles northeast of the Grand Banks, on the lookout for Soviet submarines.