The Malta-Alexandria convoy pattern

Mediterranean logistics required ships to move in both directions. Merchantmen had to leave Malta after unloading, because a ship trapped in harbor was unavailable even when it survived. Fast merchant ships were particularly valuable on dangerous routes, while slower ships could serve elsewhere. Empty ships usually returned from Malta to Alexandria; heading west without a major escort meant taking a known movement through the enemy's strongest area. Supply convoys also differed from carrier aircraft-delivery runs by Argus, Furious, and Ark Royal. Around the Taranto strike, convoy traffic and capital ship transfers overlapped with offensive operations, making the Mediterranean Fleet harder to track.