To assist in transporting the commandos, 12 Fairmile B Motor Launches (ML) were assigned from the 20th and 28th Motor Launch flotillas. These boats were re-armed with two Oerlikon 20 mm guns mounted forward and aft to complement their twin 0.303-in Lewis guns. At the last minute another four MLs were assigned from the 7th Motor Launch flotilla (see Footnotes for flotilla details). These four boats were also armed with two torpedoes each. Instead of transporting the commandos, these boats were to engage any German shipping found in the estuary. All the MLs had a auxiliary fuel tank fixed to the upper deck to increase their range. The S-class submarine would leave before the rest of the convoy and be in position to act as a navigational beacon to guide the convoy into the Loire estuary.