Destroyer Capability?

[FlankSpeed]

As Sailor Steve and others have mentioned, the lack of fully escorted convoys in the early war was nothing to do with the range of Destroyers. Infact, I believe that even smaller escort vessels like Frigates and Corvettes could easily make the crossing on one tank of fuel. It was really a question of resources...

Even though Britain was a naval super power, its fleet was stretched very thin and they just didn't have the ships to spare early in the war. Britain was a dwindling Imperial power, and its far flung colonial assets required naval protection which tied up resources. Also, much of the fleet was held back to protect the British coastline from the impending threat of invasion from across the channel, and to patrol against expected incursions from the German surface fleet, which although small was feared due to its powerful and modern heavy cruisers and battleships.

Once these threats faded away, and once the USA made the very significant contribution of lend lease, escorts could then start to be provided for most if not all of the trip.