test Haldane's diving tables and methods of stage decompression. A companion goal of the program was to develop improvements in Navy diving equipment. Throughout a three-year period, first diving in tanks ashore and then in open water in Long Island Sound from , Navy divers went progressively deeper. The publication of the first US Navy Diving Manual in 1916 and the establishment of a Navy Diving School at Newport, Rhode Island were the direct outgrowth of experience gained in the test program and the salvage. When the United States entered World War I, the staff and graduates of the school were sent to Europe, where they conducted a number of salvage operations along the French coast. On 24 May 1939 four divers would earn the Medal of Honor rescuing 33 men off the sunken . When the Squalus went down twelve divers from the Experimental Diving Unit were part of the rescue. Those directly involved in the most dangerous aspects of the rescue received the medals. WWII brought with it an expanded need for divers that began immediately after the December 7, 1941 Japanese attack on Pearl Harbor. By afternoon on the 7th nine divers from Destroyer Repair Unit 1 at San Diego were on a PBY being flown to Hawaii. Their first priority was to save lives, despite considerable effort they only found dead. They were attached to the Naval Salvage and Repair Unit created at Pearl Harbor where divers logged over 16,000 hours under diving officer Commander Haynes. Because of the shallow working depth the divers had no diving time limitation leading to fourteen hour days seven days a week. The Salvage Unit list of work included , , , , , and . They were assisted by the divers off and . Soon after the 16th Naval Construction Battalion arrived in Pearl Harbor her divers were tasked to the recovery of USS Oklahoma as well. Two steelworkers from CB 3 had previously been certified to dive with the Salvage and Repair Unit on USS West Virginia, however they were recalled because their commanding officer objected to the pay they received. This led to no more volunteers from outside the Salvage Unit being trained to dive with the Salvage Unit. At Pearl Harbor the diving assignments were split civilian/military with the civilians outside the vessels and USN inside. The divers from Destroyer Repair Unit 1 are credited with