were sunk by 10 German planes near Heligoland. These are considered as the first naval units solely destroyed by airplanes. During the war the German "Marineflieger" claimed the destruction of 270 enemy planes, 6 balloons, 2 airships, 1 Russian destroyer, 4 merchant ships, 3 submarines, 4 torpedo boats and 12 vehicles, for the loss of 170 German sea and land planes as well as 9 vehicles. Notable Marineflieger aces were Gotthard Sachsenberg (31 victories), Alexander Zenzes (18 victories), Friedrich Christiansen (13 victories, 1 airship and 1 submarine), Karl Meyer (8 victories), Karl Scharon (8 victories), and Hans Goerth (7 victories). Development of the aircraft carrier The need for a more mobile strike capacity led to the development of the aircraft carrier - the backbone of modern naval aviation. was the first purpose-built seaplane carrier and was also arguably the first modern aircraft carrier. She was originally laid down as a merchant ship, but was converted on the building stocks to be a hybrid airplane/seaplane carrier with a launch platform and the capacity to hold up to four wheeled aircraft. Launched on 5 September 1914, she served in the Dardanelles campaign and throughout World War I. During World War I the Royal Navy also used HMS Furious to experiment with the use of wheeled aircraft on ships. This ship was reconstructed three times between 1915 and 1925: first, while still under construction, it was modified to receive a flight deck on the fore-deck; in 1917 it was reconstructed with separate flight decks fore and aft of the superstructure; then finally, after the war, it was heavily reconstructed with a three-quarter length main flight deck, and a lower-level take-off only flight deck on the fore-deck. On 2 August 1917, Squadron Commander E.H. Dunning, Royal Navy, landed his Sopwith Pup aircraft on Furious in Scapa Flow, Orkney, becoming the first person to land a plane on a moving ship. He was killed five days later during another landing on Furious. was converted from an ocean liner and became the first example of what is now the standard pattern of aircraft carrier, with a full-length flight deck that allowed wheeled aircraft to take off and land. After commissioning, the ship was heavily involved for several years in the development of the optimum design for other aircraft carriers. Argus also evaluated various types of arresting gear, general procedures needed to operate a number of aircraft