One of the best and best known diving helmets in the world is the US Navy Mark V. Until about 1912 there was hardly any serious (deep) diving activity in the US Navy. Commercial Morse and Schrader helmets were used. US Navy gunner George D. Stillson wrote a letter to the Bureau of Construction and Repair (now the Bureau of Ships) in which he complained about the Navy's equipment and diving techniques. He suggested to check the practicability of Haldane's stage method of decompression and to improve the standard Navy diving gear to permit deeper dives. The Bureau gave Stillson the assignment. It took several years and the help of a team of military and commercial diving experts to complete the heavy task. The design of the new diving helmet was based on commercial Morse and Schrader helmets of that time and the team also tested Siebe and Draeger equipment. Extensive tests were conducted in diving tanks ashore and later from the U.S.S. Walke in Long Island Sound. In 1915 Stillson reported to the bureau in the Report on Deep diving tests. It contained drawings and descriptions of the precursor of the MkV and of a lot of other navy diving equipment. Stillson layed the foundations for professional diving in the US Navy.