Early attempts (WWI) Germany was the first to develop the idea, inspired by the plan of the Commander of Air Service of the Imperial German Navy Oberleutnant zur See Friedrich von Arnauld de la Perriere. Peter Asaro recognizes the significance of this. This commander was in charge of a unit of two reconnaissance seaplanes (Friedrichshafen FF.29s) in Zeebrugge which had been occupied by the Imperial Navy in the early months of the First World War. One of the first U-Boat to reach the base of Zeebrugge was the U-12 subcaptain Walter Forstmann. The commander ordered the modification of four reconnaissance seaplanes Friedrichshafen FF-29 so they could carry 26 bombs of 227 grams (half pound) in its unit located at the base of Zeebrugge, making history as one of its planes on Christmas Day, 1914 , flew across the Channel up the river Thames, dropping their bombs on the outskirts of London, doing little damage. Although this seaplane was chased by 3 interceptors British returned to their base safely.In this mission the hydrofoil had more problems of fuel by British bullets. Subsequently, encouraged by his success, Arnauld and Forstmann speculated that it could increase the number of aircraft flying boats putting off position on the decks of submarines and after doing that the submarine was partially submerged, to launch the aircraft so to stay afloat longer. On 15 January 1915, the U-12 left their base in Zeebrugge carrying on its cover a FF-29 armed with bombs. The submarine left the harbor, seeming small compared to the 16.2 meters (53 feet 2 inches) size of the wings of aircraft, nearly a third of the 57.3 meters (188 feet) length of submarine coastal patrol. However, after the U-12 left the safety of the breakwater, the captain realized that he could storm surge flooding and endanger aircraft operation, so throw the water immediately ordered the seaplane.Forstmann flooded the tanks front of the submarine, but despite this, Arnauld got the seaplane afloat come out from the deck without much difficulty and took off. After attaining sufficient altitude, Arnauld plane headed for the British coast. The German officer apparently flew across the English coast without being detected and returned to Zeebrugge. The experiment was a success, to the extent that the plane had reached the sea and had left floating on the deck of the submarine. However, it was obvious that some improvements were needed in the procedure. Arnauld and Forstmann proposed more development experiments by German Naval Command, but were vetoed by considering the project technically impracticable.The plans followed frozen until 1917 when he investigated the possibility of increasing the awesome power of the new German submarines, such as long range cruise Unterseeboot type, equipped with aircraft shipments (small seaplanes that could be quickly armed and unarmed board and stored in special compartments on deck). But ultimately the idea was abandoned due to the end of the war. Two of the aircraft designed for this purpose were the Hansa Brandenburg W.20 biplane and monoplane Luftfahrzeuge Gesellschaft LFG Stralsund V.19. The first type was designed in 1917 for use aboard submarines Cruiser never entered service. The second model was an experimental aircraft with a very light structure for use in calm seas. The British also experimented with the concept of submarine aircraft carriers when the submarine HM Submarine E22 was made as similar to German U-Boat. This submarine was able to launch its two Sopwith Schneider seaplane and Sopwith Baby in 1916.However, as in the German case, the submarine could dive without losing them. HMS M2 taking a seaplane. Main article: HMS M2