Nearly all of Coastal Commands aircraft were obsolete in 1939 like the Avro Anson, and only slowly new types were on the way: The Short Sunderland and the american Lockheed Hudson and PBY Catalina. Other commands had to do part of the duties with Bristol Blenheims and heavier aircraft. When the battle of the Atlantic began, the main task was to keep the sealanes open for convoys carrying vital supplies. But Coastal Command wasn't able to patrol the Atlantic far enough to the west, and out there were rich hunting grounds for the german u-boats, until a suitable aircraft became available: The american B-24 Liberator.
Carl Vendler
