For 12 months, No. 120 Squadron RAF of Coastal Command with its handful of worn and modified early model Liberators supplied the only air cover for convoys in the Atlantic Gap, the Liberator being the only airplane with sufficient range. The VLR Liberators sacrificed some armor and often gun turrets to save weight, while carrying extra aviation gasoline in their bomb-bay tanks. Liberators were equipped with ASV Mk. II radar, which together with the Leigh light, gave them the ability to hunt U-boats by day and by night. Before the Leigh light not a single enemy submarine had been sunk in over 5 months, but in combination with radar it was so overwhelmingly effective that many German submarine crews chose to surface during the day so that they could at least see the aircraft attacking them and have a chance to fire their anti-aircraft weaponry in defense.