Time In The Atlantic

When a convoy was attacked in the North Atlantic the events were reviewed by:

• The Anti Submarine Warfare Division, Whitehall
• Shipping Casualties Section, Trade Division
• The Admiralty

Despite their experience the Anti Submarine Warfare Division were confused as to which time zone was being used in certain reports. They did not know what East Atlantic Summer Time was and had to write to the Commodore of HX-126 Admiral F B Watson asking for clarification. Admiral Watson wrote back: his hand written explanation is on embossed headed note paper from his yacht Fortis in Bosham, Hampshire.

Atlantic Summer Time is Halifax time +1 or GMT -3. The ships kept AST all the way across "it is what we lived by". 


Further confusion arises because signal times were recorded in the time zone of the local escorts and so EAST in Canada, GMT for Iceland and BMT for the home escort.

I cannot be sure what BMT is. Clearly it is not GMT so it seems likely to be the time zone of Britain in Summer, not British Summer Time, because during World War II Britain stayed on BST through the winter and still advanced an hour in the Summer. So it seems likely that BMT is GMT +2 (and so EAST +5) and probably stands for British Mean Time.