Duties included the salvage and repair of ships, construction work and military operations, and the Battle of Mobile Bay during the American Civil War.

Preparations for the battle included the sending of swimmers to clear mines from the path of Admiral Farragut's ships, that had been planted by Confederate States forces to prevent entrance to the bay.

[2] In 1898, Navy divers were briefly involved in an international crisis when the second-class armored battleship USS Maine was sunk by a mysterious explosion while anchored in the harbor at Havana, Cuba.

However, throughout the period of 1912–1939, the development of the Navy's F-class, H-class and S-class submarines was marred by a series of accidents, collisions, and sinkings.

[3] In that year, Chief Gunner George D. Stillson set up a program to test Haldane's diving tables and methods of stage decompression.

Throughout a three-year period, first diving in tanks ashore and then in open water in Long Island Sound from USS Walke,[3] Navy divers went progressively deeper.

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.

WWII brought with it an expanded need for divers that began immediately after the December 7, 1941 Japanese attack on Pearl Harbor.

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.

[10] Soon after the 16th Naval Construction Battalion arrived in Pearl Harbor her divers were tasked to the recovery of USS Oklahoma as well.

[11] 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.

[15] The creation of Naval Construction Battalions to build advance bases in the Pacific Theater put more diving assignments in front of the Navy, enough that the Seabees had a school of their own to qualify 2nd class divers.

In the Aleutian Islands Naval Construction Battalion 4 had divers doing salvage on the Russian freighter SS Turksib in 42 °F (6 °C) water.

At Halavo on Florida Island, divers from the 27th CB recovered a Disburser's safe full of money plus changed 160 props on vessels of all sizes.

[19] However, the divers of CB 96 used 1,727,250 lbs of dynamite to blast 423,300 cubic yards (323,600 m3) of coral for the ship repair facility on Manicani Island, as an element of the Naval Operating Base Leyte-Samar.

In New York, USS Lafayette capsized at the dock leading to the Navy creating a Salvage school right there to deal with the issue.

Two divers plus their support teams were put aboard USS Seminole in response to a secret dispatch from Commander South Service Force Pacific.

[21] Earlier in the year, at Kamimbo Bay, USS Ortolan divers recovered a pile of documents off the partially sunk Japanese submarine I-1 that was turned over to intelligence.

There they salvaged code books, maps of Japanese fortifications on Luzon plus 500,000 yen; it was a major intelligence coup.

[22][23] When Chanticleer first left the States part of its mission was to provide diver training to the fleet based out of Freemantle, Australia.

However, the U.S. Army and Navy put together a hard hat diving unit in August 1945 that recovered millions of Pesos off USS Teak.

[3] A few months after Pearl Harbor Congress authorized a change so that divers were paid $5.00/hr for any dive certified "extremely hazardous".

[26] The Diving officers did written reports of all observations, C.2.9 identifies what was found on USS Arkansas on 21 August 1947 with everything underwater photographed.

[25]: 271–2  Divers carried a watertight Geiger tube that was monitored by their support crews so that they could be warned and retracted from radioactive hot spots.

SEALAB I, II, and III were experimental underwater habitats developed by the United States Navy in the 1960s to prove the viability of saturation diving and humans living in isolation for extended periods of time.

The knowledge gained from the SEALAB expeditions helped advance the science of deep sea diving and rescue, and contributed to the understanding of the psychological and physiological strains humans can endure.

[33] Still in service, USS Chanticleer was involved with RVN diving operations at Nha Trang during the Vietnam War.

Some of the subjects include: Hyperbaric Chamber, SCUBA, MK-16 Rebreather, Surface Supplied Air, and Mixed Gas Supervisor.

Because their area of operations are so varied, they can be required to utilize any type of diving equipment for use in any depth or temperature in any part of the world.

Diving medical personnel evaluate the fitness of divers before operations begin and are prepared to handle any emergencies which might arise.