torpedo warhead's detonation. Abreast the boiler rooms were very deep coal bunkers that were also intended to help absorb a torpedo detonation. Construction and conversion Béarn was laid down at the Forges et Chantiers de la Méditerranée shipyard in La Seyne on 10 January 1914. The outbreak of World War I in August 1914 interrupted construction, which was halted for the duration of the conflict. By that time, work on Béarn had not significantly progressed: her hull was only 8–10 percent complete and her engines were only 25 percent finished. Her boilers were 17 percent assembled, and her turrets were 20 percent completed. The hull was launched on 15 April 1920 to clear the slipway, though the had not yet decided what to do with it. That year, a French delegation visited the British aircraft carrier , and out of this visit came a proposal to convert one of the incomplete Normandie-class battleships into an aircraft carrier, which was designated Project 171. The first step was to conduct trials using Béarns hull which was only complete up to the lower armored deck and lacked her belt armor and propulsion machinery. A wooden platform was built on the lower deck with an improvised arresting gear system that was weighted down with sandbags. Paul Teste conducted the first tests in October using British Sopwith 1½ Strutters. Further trials were conducted the following year with the Hanriot HD.3. Still undecided on whether to complete the ship as either a battleship or an aircraft carrier, the 's hand was forced when the Washington Naval Treaty was signed on 6 February 1922 and ruled out the former possibility. On 18 April the decided that Béarn, rather than any of her sisters, would be converted into an aircraft carrier because her construction was the least advanced and would thus be the cheapest to convert. Her four sisters, which were closer to completion, were instead broken up for scrap. Much of the equipment from these ships was used to complete Béarn and several cruisers that had been ordered in 1922. A contract for the conversion was signed with her builder on 4 August 1923 for 66.33 million French francs. General characteristics and machinery Béarn was long between perpendiculars and long overall. She had a beam of at the waterline and at the flight deck. She displaced at standard load and at full load, which gave her a