On 25 March, Force 70, now consisting of "Saumarez", "Virago", "Vigilant" and "Volage" sailed on an anti-shipping sweep between the Andamans and the Malayan coast (Operation On Board). Next day, Force 70 located and attacked an enemy convoy of four transports escorted by two Japanese anti-submarine vessels that were en route from Singapore to Port Blair with supplies, troops and "comfort women". Ships' gunfire and torpedoes were used without success until Liberator aircraft, from No. 222 Group RAF, provided support. The four transports were then sunk by a series of air and surface attacks, during which one Liberator crashed. There were 52 Japanese survivors taken prisoner from the convoy and delivered to Trincomalee on 28 March.