Forty-six A boats were ordered under the 1943 Programme, and the first-of-class, Amphion, was laid down at Vickers on 14th November, 1943 and launched on 31st August, 1944. Only Amphion and Astute, also Barrow-built, were completed before the end of the war, but neither were involved in any hostilities. With the conclusion of the war imminent, 30 of the 46 ordered boats were cancelled - and of the 16 that remained, Vickers constructed ten at Barrow.
A Class submarines were over 280 feet long and displaced 1385 tons (surfaced). Their two Admiralty diesels developed 4,300 hp, which gave a surface speed of 18.5 knots. The submerged speed was 8 knots, produced by two English Electric motors generating 1250 hp. The radius of action of the A Class was 10 500 miles on the surface at 11 knots and up to 90 miles submerged at 3 knots.
