Type 15 frigates A successful conversion

摘要

Nick Hall traces the development of the Royal Navy's Type 15 frigates, a successful series of Anti Submarine Warfare ships which owed its origin to several classes of redundant World WarⅡ destroyers. Britain was very nearly brought to its knees by Axis submarine successes during World War Ⅱ and the Battle of the Atlantic was fought hard and long before it was won. With Allied assistance, Britain had established itself as the world leader in Anti Submarine Warfare (ASW) and it was imperative to the country's post-war interests that this position was maintained. This posed a serious challenge, however, because submarine capabilities had improved dramatically towards the end of the war. The development of the Snorkel enabled submarines to remain submerged for longer periods while, more importantly, boats were developed which had much higher underwater speeds. The advanced hull design Type XXI U-boat, for example, could run submerged at 16 knots, more than double the speed of earlier boats. Even more alarming from an ASW point of view were advanced propulsion methods such as Walter closed cycle hydrogen peroxide motors enabling submarines to maintain previously unheard of submerged speeds of well in excess of 20 knots.