King George V Class Battleship (1939) - Design and Description - Propulsion

Propulsion

The King George Vs were the first British battleships to alternate engine rooms and boilers in the machinery spaces, which reduced the likelihood of one hit causing the loss of all power. The machinery was arranged in four engine (turbine) rooms and four boiler rooms, with the 8 machinery compartments alternating in pairs of engine or boiler rooms. Each pair of boiler rooms formed a unit with a pair of engine rooms. Nominal full power was 110,000 shaft horsepower at 230 rpm with 400 pounds per square inch (28 bar) steam at 700 °F (371 °C). The machinery was designed to operate at an overload power of 125,000 shp and Prince of Wales' "...main machinery steamed at overload powers of 128,000 to 134,000 shaft horsepower with no difficulties..." during the hunt for the Bismarck. The Admiralty boilers operated very efficiently and similar boilers of nearly identical power, fitted to Warspite during her rebuilding in 1937, achieved a full power specific fuel consumption of 0.748 lb per shp on trials which compared favourably with contemporary battleships. After 1942 the Royal Navy was forced to use fuel oils with considerably higher viscosity and greater seawater content than these boilers could efficiently use. The poor quality of the oil fuel combined with the seawater contamination to reduce the efficiency of the steam power plant and increased the maintenance required. By 1944 the specific full power fuel consumption had increased to 0.8 lb per shp and boiler maintenance was becoming increasingly difficult. The Admiralty had been aware of this problem and were designing new types of oil sprayers and burners that could burn the available fuel oil much more efficiently, and sometime after 1944, Duke of York and Anson were fitted with new, higher pressure, oil sprayers and burners that restored the boilers to full efficiency. These same oil sprayers and burners were used in Vanguard along with other detail improvements so that Vanguard achieved a full power specific fuel consumption of 0.63 lb per shp while using the same steam pressures and temperatures as used on the KGV class.