The key man in the Mark V story is U.S. Navy Gunner G.D. Stillson. In 1912, he submitted a report suggesting the U.S. Navy follow the example set by the British Royal Navy which had undertaken a long series of diving tests in 1906-7 making: “diving in great depths of water practical and safe”. These tests

resulted in the Admiralty Diving Manual of 1907.
In 1914, Gunner Stillson and his assembled group of U.S. Navy divers dove the U.S. helmets made by Morse Diving Equipment Co., Inc. and Schrader and Sons, Inc., the British helmets made by Seibe Gorman, and the German helmets made by Draeger Werk. Gunner Stillson took the best attributes from each of these helmets and incorporated them into the USN Mark V diving helmet in 1915. The U.S. Navy Diving Manual was subsequently published in 1916. The Mark V remains a proud symbol of the U.S. Navy’s commitment and accomplishments in Diving and Salvage.

Statistics:
Helmet Weight= 56 pounds
Weight Belt= 84 pounds
Diving Boots= 35 pounds
Diving Dress= 15 pounds
Total= 190 pounds
Diving depths: Air- 190 ft. Gas- 300 ft.