Capt Maino des Granges, former OIC of NEDU, passed August 19, 2009 at the age of 91.

We are sorry to report that Maino des Granges has passed. He was a retired Navy Captain and in the 1950s he was the OIC of NEDU in the Washington Navy Yard. During his time at NEDU the dive tables that we used for over 50 years were developed. We've attached his obituary.

22Sep09 - As a youth growing up in Southern California, Maino des Granges developed a love of diving, inventing and building.

As a Navy officer and entrepreneur, he used his skills to come up with inventions to assist in diving and construction. As a retiree wanting to improve his golf game, he designed and built a collapsible driving-range cage and putting green in his yard, complete with sand trap.

Capt. des Granges died Aug. 19 after suffering a heart attack while attending a Padres game. He was 91.

Friends and relatives said Capt. des Granges was a quiet, unassuming, self-made man who enjoyed coming up with solutions to problems.

After enlisting in the Navy in 1936, he was selected for appointment to the Naval Academy in 1938. He was among those who graduated early because of World War II.

He graduated from the academy in December 1941 and was assigned to submarine patrol in January 1942. After completing three war patrols, he was able to attend submarine school. "He was pretty sharp," said friend and fellow Navy veteran Charles Bishop. "He was made commanding officer (in 1943) and was one of the youngest at the time."

In the 1950s, Capt. des Granges was officer in charge of the Navy Experimental Diving Unit in Washington, D.C. "He developed the Navy's first set of diving tables. ... Everybody that goes diving uses the diving tables he developed," Bishop said, referring to the invention of a handheld wheel computer that was widely used and served as the prototype of many dive computers used today.

Capt. des Granges was a "fearless, remarkable man's man," son-in-law Ned Chambers said. "I think I hit the father-in-law lotto. ... He was the most honorable, phenomenal human being."

Although he was given six months to live after undergoing melanoma surgery several decades ago, Capt. des Granges "just went on with his life and beat it," Chambers said.

He enjoyed tinkering around his home and yard into his late 80s. Chambers remembered getting a call from his mother-in-law several years ago when Capt. des Granges had fallen and dislocated his hip while building a concrete wall in his yard. "The paramedics were there and he was telling them, `Just pull it back in so I can get back to work.' "

"He was his own man," Chambers said, noting that Capt. des Granges' 1963 Plymouth bore a sticker on the front that identified him as a Navy captain, while a rear sticker identified him as a Libertarian.

After retiring from the Navy in 1966, Capt. des Granges became the owner and operator of Superior CATV Construction, a major installer of underground cable. The business had nearly 200 employees at one time and had offices in El Cajon and Huntington Beach. Capt. des Granges was active in the El Cajon Chamber of Commerce until he sold the company in the mid-1980s.

"He was energetic and innovative, and everybody who worked with him just loved him," said Wade Harris, who served under Capt. des Granges when he was division commander and Harris was an executive officer. "He was one of the finest naval officers I ever met. He had a quiet, unassuming personality, but he was outstanding at his job."

Maino des Granges was born Aug. 2, 1918, in Fullerton to Paul and Julia des Granges. He graduated from Fullerton High School.

He married the former Dorothy Beckley in 1942. They settled in San Diego in 1964, when he was stationed as commanding officer of the submarine tender Nereus. He was a member of the Yacht Club and enjoyed playing golf and bridge.

He is survived by his wife, Dorothy, of Point Loma; daughters, Jeanne Vivoli and Anne Chambers of San Diego; son, Paul of Portland, Ore.; four grandchildren; and one great-grandchild. He was predeceased by a sister, Pauline des Granges, a former director of the San Diego Park and Recreation Department.

This Day in Diving History -- September 13, 1939 -- USS SQUALUS (SS-192) salvaged

This Day in Diving History -- September 13, 1939 -- USS SQUALUS (SS-192) salvaged.

On 13 September, after long and difficult salvage operations, SQUALUS was raised and towed into the Portsmouth Navy Yard. The boat was formally decommissioned on 15 November, renamed USS SAILFISH, and recommissioned on 15 May 1940. This operation took close to four months to complete, had many firsts and started only two days after the rescue (see This Day in Diving History sent May 21st).

The decision to salvage SQUALUS was made almost immediately. The Navy felt it important to raise SQUALUS as she incorporated a succession of new design features. With a thorough investigation of why she sank, more confidence could be placed in the new construction, or alteration of existing designs could be undertaken. Furthermore, given similar previous accidents, it was necessary to determine a cause.


HEO2 / SURFACE DECOMPRESSION
The salvage operation of the SQUALUS began on May 27, 1939 with the first operational helium-oxygen dive by Chief William Badders and first use of Sur-D procedures off of USS FALCON (ASR-2). This new breathing medium and decompression procedures were critical to the salvage operation due to the depth (240 feet). In the words of Commander Momsen:

"The greatest single development produced on this job was the decompression system. Divers were brought by stages, calculated to be safe, to 50 feet. From this depth they were brought quickly to the surface, undressed and placed in a pressure tank within five minutes after surfacing. There he was fitted with a mask and given pure oxygen for a time sufficient to remove all of the excess gas from his body. Fifty feet of salt water is equivalent to 1-1/2 atmospheres of pressure which added to the atmospheric pressure gives us 2-1/2 absolute. At this pressure the blood stream can handle in physical solution just about the amount of oxygen that is required by the body. Thus the blood stream as transportation is free to carry the greatest amount of the helium away to the lungs. Since the solubility of a gas in a liquid varies as the pressure, at a pressure of less than 2-1/2 atmospheres, the carrying capacity of the blood would be reduced, hence it would take longer to remove the gas."

There were only 2 cases of the bends in the entire job with a total of 628 dives.

SALVAGE OPERATIONS
Many of the procedures used on previous submarine salvage operations (like the USS SKATE) would be used on the SQUALUS. Lifting pontoons were primarily used, but there are some significant differences that made the SQUALUS operation noteworthy. The salvage plan called for raising SQUALUS with pontoons and her remaining internal buoyancy. To accomplish this, the salvage was planned and conducted in three distinct stages. Unlike previous pontoon salvage operations, control pontoons limited the distance the ship was lifted in any single lift. The reason for this is when pontoons and the vessel's own buoyancy are used, the exact locations of the centers of gravity and buoyancy cannot be determined; thus one end always rises first. If the rise of the upper end is not constrained, a sharp angle will result and air will spill from open bottom ballast tanks. To prevent a sharp angle, SQUALUS would be lifted a short distance, towed submerged to shallow water, and lifted again. To limit the distance the submarine was raised on each lift, the pontoons were arranged at different levels between the surface and the submarine. When the uppermost pontoons reached the surface, their lift would be lost and SQUALUS would hang in midwater, supported by her internal buoyancy and that of the submerged pontoons. The upper pontoons were known as the control pontoons because they controlled the height of the lift (see attached PowerPoint slide). After weeks of grueling work both by divers and topside personnel, all was ready for the first lift. Commander Momsen described what happened:


"At the end of fifty days work, the first lift was attempted. We raised the stern successfully then the bow. The bow came up like a mad tornado, out of control. Pontoons were smashed, hoses cut and I might add hearts were broken. It was the 13th of the month, July. Another 20 days of mopping up was required before we could again rig for another try. The second try was successful."


Pontoons were rerigged for the second lift so that more positive control over the bow was maintained. SQUALUS was raised 70 feet and towed toward Portsmouth until she grounded. The pontoons were rerigged for lifting in the shallower water and she was again lifted successfully and eventually towed to drydock (Sept 15, 1939); 113 days after it sank. The vessel was exactly one year old.

USS SAILFISH
After reconditioning, repair, and overhaul, the submarine was recommissioned and renamed USS SAILFISH (SS-192) on 9 February 1940. Once sea trials were complete, she departed Portsmouth on 16 January 1941 and headed for the Pacific. Transiting the Panama Canal, she refueled at San Diego and arrived at Pearl Harbor in early March. The submarine then sailed west to the Philippines, where she operated out of the Cavite Navy Yard with Submarines, Asiatic Fleet. She was in port when the Japanese attacked Pearl Harbor on 7 December 1941. SAILFISH conducted 12 patrols and would be awarded nine battle stars for her service in World War II Service. It is especially note-worthy that several of the SQUALUS survivors served aboard SAILFISH during some of these war patrols.

During the Pacific War, the captain of the renamed ship issued standing orders if any man on the boat said the word "Squalus", he was to be marooned at the next port of call. This led to crew members referring to their vessel as "Squailfish". That went over almost as well; a court martial was threatened for anyone heard using it.

President Roosevelt visited during the salvage operations and formally commended the "devotion to duty, courage, skill, initiative, and self sacrifice" of the officers and men who salvaged the sunken submarine. Every Navy Diver who worked on the SQUALUS received an award ranging Congressional Medals of Honor (4), to Navy Crosses (49), to citations from the Secretary of the Navy (4).

Books:
1. "Back from the Deep: The Strange Story of the Sister Subs Squalus and Sculpin" by Carl Lavo
2. "Blow All Ballast! The Story of the Squalus" by Nat Barrows
3. "The Terrible Hours: The Greatest Submarine Rescue in History" by Peter Maas

Note: SQUALUS/SAILFISH's conning tower stands today as a memorial to the lost crew of the USS SQUALUS at the Portsmouth Naval Shipyard.

H/Y

This Day in American History -- September 11, 2001

There is a "This Day in Diving History" email set to be sent today. It would be inappropriate to do so on a day that we should all be in remembrance of one event and one event alone....instead it will be sent on Monday. Doing a complete write-up of what happened 8 short years ago would be redundant for those that receive these emails. As soldiers and sailors in the world's greatest military, we have the events of that day firmly branded into our memories. Instead, here are some numbers that came as a result of 9/11:

1) Total number killed in attacks: 2,993. A little perspective here: This number is higher than the combined total of Navy Divers, EOD Techs and Special Warfare Combatant Crewmen (SWCC) personnel currently serving on active duty.

2) Number of firefighters/paramedics and police officers killed: 403

3) Number of U.S. casualties ISO the GWOT (as of June 24, 2009): 4,316

4) Number of nations whose citizens were killed in attacks: 115 (there are 195 total countries in the world today)

5) Bodies found "intact": 289

6) Body parts found: 19,858

7) Number of families who got no remains: 1,717

8) Estimated number of children who lost a parent: 3,051

9) Percentage of Americans who knew someone hurt or killed in the attacks: 20

10) Tons of debris removed from site: 1,506,124. This number is far higher than the combined dead weight of every aircraft carrier currently commissioned in the Navy.

11) Days fires continued to burn after the attack: 99

12) Estimated cost of cleanup: $600 million

13) Terrorist attacks on U.S. soil since 9/11: 0

In an age were second guessing has become second nature especially in the media and political realm, today should reinforce why we serve and sacrifice. In the words of Father Dennis O'Brien, US Marine Corp. Chaplain:

"It is the soldier, not the reporter, who has given us the freedom of the press.
It is the soldier, not the poet, who has given us the freedom of speech.
It is the soldier, not the campus organizer, who gives us the freedom to demonstrate.
It is the soldier who salutes the flag, who serves beneath the flag, and whose coffin is draped by the flag, who allows the protester to burn the flag."

H/Y

"America will never run... And we will always be grateful that liberty has found such brave defenders."
George W. Bush
Official Navy Photo: September 13, 2001 from the deck of the USNS Comfort

Photographer: HMC (SEL) (DV/PJ/FMF) Michael S. Duff

This Day in Diving History -- 29 August 1915 -- USS SKATE raised (late entry)

This Day in Diving History -- 29 August 1915 -- USS SKATE (F-4) raised.

The Navy's first deep-sea submarine salvage was of the USS SKATE (F-4), which was lost in approximately 51 fathoms (306 feet) while making a short submerged run off the island of Oahu, Hawaii, in March 1915. This was the Navy's first loss of submarine and crew.


The F-4 had a length of 142 feet, with a submerged displacement of 400 tons and a designed depth of 200 feet. After the accident, an oil slick and air bubbles about 2 miles from the harbor entrance lead to dragging operations that positively located the boat; there were no apparent signs of life. The submarine lay far deeper than any divers had ever descended with existing equipment and methods. In and effort to reach the boat on the day of the loss; two Navy Divers dove to a depth of 190 and 215 feet, but neither reached or sighted the vessel. The only chance of saving any possible survivors was to drag the boat into shallow water because no lifting gear could be made and rigged in the time available. Dragging would work only if the boat was not completely flooded. Sweeps were made by the NAVAJO and INTREPID to pass a wire rope around the hull and drag it into shallow water. An attempt at this was made the following day, but the boat could not be moved. Rescuing the crew appeared hopeless but one more attempt was warranted. A dredge was brought to the scene; if a portion of the submarine remained unflooded and buoyant, there was a possibility of moving the boat into shallow water by heaving with the dredge and towing with tugs. No progress could be made (one of the wires parted at its maximum load). This answered the question whether the F-4 was filled with water -- it was, and rescue effort was regretfully concluded.


Because the F-4 was the Navy's first submarine loss, there was an intense desire within the Navy to determine the cause of the casualty. There was also a huge public outcry for the recovery of the bodies of the crew. Naval Constructor LCDR Julius Furer, who was in Hawaii for the construction of the new Naval Station at Pearl Harbor, was placed in charge of the technical side of salvage. After evaluation the situation and consultation with Navy Salvors, it was determined that multiple short lifts and tows were the only feasible way of raising the boat. Faced with a lack of specialized equipment for the job and a base under construction in Hawaii; Salvors were forced to do what they do best - improvise with what was on hand to get the job done. Two sturdily constructed 104x36 foot barges belonging to a local construction company had the strength to support the downed submarine. A lifting system was built using I-beams planned for a coal storage facility, sugar mill shafts were used as windlasses along with miscellaneous machinery that was either available or made for the job.


Knowing that the positions of the lift slings would be crucial to the success of the salvage and that their positions could only be verified visually, five of the Navy's top Divers were ordered in from the Navy Yard. At the time the Navy Yard was responsible for the test and review of all diving equipment and techniques. These divers were Gunner Stillson, Frank Crilley, Stephen Drellishak, Frederick Nilson and William Loughman. Chief Crilley made the first dive just two days after arrival. He reached the F-4, more than 300 feet down, and reported that the boat was upright but the slings would have to be moved. The difficulty of working at this depth cannot be overstated. Keep in mind that all of these dives were conducted with air -- breathing HE02 had not been discovered yet. The futility of attempting to work at these depths was demonstrated when a diver remained on the bottom for thirty minutes trying to pass a small reeving line. He was unaware of fatigue on the bottom, but collapsed from exhaustion on the surface and did not regain strength for several days. In another instance Chief Loughman became entangled in a steel hawser at a depth of 250 feet down breaking his hip in process. Loughman fell unconscious and GMC Frank W. Crilley dove in after him, disregarding personal safety. He found Loughman and worked for an hour and a half to free him. For his heroism, Crilley became the first Navy Diver to be awarded the Medal of Honor on February 15, 1929. For more info on this heroic rescue see the "This Day in Diving History" email sent April 17.

After multiple lifts over the course of months the submarine had been moved to 48 feet of water by June. The problem was now how to move her in one lift through Honolulu Harbor with out breaking the sub up which would totally block the harbor. It also had to achieve a depth of 25 feet or less to fit into existing drydocks. In order to accomplish this, Salvors developed what would be known as the submarine pontoon salvage method. To do this, chains were moved under the boat and attached to huge pontoons that were built for this operation. These pontoons were 32 feet long with a lifting capacity of 420 tons and were built with wooden sheething all around to prevent impact, chaffing, or puncture to the hull due to frequent contact. On 29 August, the pontoons were blown dry, the submarine was towed into the harbor and placed in drydock. It was immediately discovered that the cause of the accident was leakage through rivet holes where the rivets had been eaten away by battery acid. This resulted in immediate design changes to all U.S. Navy Submarines.

The methods, lessons learned, and equipment employed in this operation would be used during the raising of the USS SQUALUS (SS-192) years later.


Note: For more reading about this historic salvage operation check out the following hyperlink to UnderSea Warfare Magazine

http://www.navy.mil/navydata/cno/n87/usw/issue_29/f4.html

H/Y

This Week in Diving History -- August 28, 1965 -- SEALAB II

** This Week in Diving History -- August 28, 1965 -- SEALAB II leaves surface **

On August 28, 1965, the first of three teams of divers moved into what became known as the "Tilton Hilton" (because of the slope of the landing site) also known as SEALAB II. This first day of the operation happened to be one of the divers involved birthday; Bob Barth, who turns 79 today-Happy Birthday Bob!

SEALAB II rested at a depth of 205 ft 65 miles off the coast of LaJolla, CA. Whereas SEALAB I tested and proved the concept of saturation diving, SEALAB II provided evidence that useful work could be done. The Navy conducted physiological and psychological studies to determine man's effectiveness underwater for an extended period. Navy Divers not only evaluated the structural engineering of the habitat. They did things like working on a mock-up of a submarine hull, tested undersea tools, conducted salvage ops using syntactic foam; they set up a weather station, mined ore samples, experimented with plants, and studied ocean floor geology just to name a few things. They also experimented with a trained porpoise named Tuffy from the U.S. Navy Marine Mammal Program, to do courier work between the habitat and the surface.

Each team spent 15 days in the habitat, but aquanaut/astronaut Scott Carpenter remained below for a record 30 days. During that time, he was able to speak with astronaut Gordon Cooper who was in the Gemini space capsule, orbiting the Earth. Also a congratulatory telephone call was arranged between President Lyndon B. Johnson and Scott Carpenter while he was still under pressure. The fact that Carpenter was breathing Helium-Oxygen made him sound unintelligible to operators. Much was learned about working in the ocean and contributions were made to a large number of undersea science and engineering disciplines. SEALAB II was no doubt a success and represented another large step forward in enabling human beings to live and work in a hostile environment. SEALAB II was designed, built, and outfitted at Hunter's Point Naval Shipyard in San Francisco at a cost of $850,000. It was designed to house ten men at a depth of 200 feet for 30 days. The habitat was 50' long and 12' in diameter, and included four separate areas: entry, laboratory, galley, and living spaces. Entry while on the ocean floor was from below the habitat, with divers emerging into the pressurized habitat through an open moon pool.

Construction of SEALAB II's cylinder end bell used technology ahead of its time. The large dish-shaped cap was formed from a sheet of one-inch thick flat steel placed over a die. In order to shape it, one hundred pounds of C-4 plastic explosive were distributed on the side of the blank opposite the die. The whole package-die, blank, and charge, weighing 60 tons total-was lowered 30 feet beneath the surface of San Francisco Bay where the explosive was detonated. In approximately .004 seconds the end bell was formed. Explosive metal shaping on this scale had never been attempted before. If you would like to see this end bell, visit the Naval Undersea Museum in Keyport, WA.

Note: This photo entitled "Bob-Barth-Scott-Carpenter-Sealab.jpg"; is a picture taken at the dive station on the support barge of Sealab Two, Bob Barth is shaking Wilbur Eaton's hand as he and Scott Carpenter are making ready to swim down to the house (they were the first two to leave surface).

H/Y

Diving History -- Diving on the Silver Screen

Diving History -- Diving in the Movies.

The idea of diving into an unknown potentially dangerous environment has long appealed to writers in Hollywood. The recent movie Men of Honor is very familiar to everyone in the diving community. The following are a few other notable movies that come to mind:

James Bond: Ian Fleming's fictional MI6 agent James Bond had several movies that involved diving. Two of the most diving intensive ones were:
-Thunder ball (1965). During an underwater battle with SPECTRE (the movies bad guys), Bond is rescued by a military unit who parachutes to the area for underwater battle against the SPECTRE divers. Bond joins the fray, killing them off with high tech submarine weapons, his knife and his hands.
-For Your Eyes Only (1981). 007 goes deep underwater in a mini sub
that he locks out of and has an underwater battle with a bad-guy wearing a JIM one atmosphere diving suit. Bond plants an explosive charge on the back of the suit and manages to escape just in time before it explodes.

John Wayne: The Duke didn't fare to as well as a Diver. He starred in two movies as a Deep Sea Diver and died in both of them.
-Reap the Wild Wind (1942). After a ship goes down at sea, John
Wayne suits up in a deep sea diving rig to confirm if a woman was trapped inside and died. While down in the wreck he discovers proof that she was on board and had drowned. As they are leaving not only does a massive storm
hit but a giant squid attacks his dive buddy (talk about a bad day). John
Wayne could have easily escaped but attacks the squid, saving his dive buddy but sacrifices himself in the process.
-Wake of the Red Witch (1948). While retrieving treasure/gold on a
sunken ship, the ship begins to shift causing debris from the ship to fall all around him. Eventually this debris piles on the Duke, trapping him and leading to his ultimate demise.

Gojira (Godzilla 1954)
-After reaping havoc, death and destruction on Tokyo; Godzilla
returns to Tokyo Bay for a little underwater R&R. After all else fails, the good people of Tokyo turn to the only ones that can save them from the monster -- two hard-hat divers. Both divers descend into Tokyo Bay with an "Oxygen Destroyer Bomb", the ultimate weapon that destroys what else -- oxygen. Once on the bottom, they spot Godzilla resting underwater.
Seemingly unaware of the divers, Godzilla slowly wanders around as the divers activate the Oxygen Destroyer. As one of the divers watches Godzilla dying from the weapon, he cuts his own umbilical and dies with Godzilla, sacrificing himself so that his knowledge of the horrible weapon will not be known to the world. A dying Godzilla surfaces, lets out a final scream, and sinks to the bottom, disintegrating into a skeleton, and then into nothingness.

The Deep (1977)
-Nick Nolte and Jacqueline Bisset play a young couple enjoying a
tropical vacation who discover a glass ampoule while diving off the coast of Bermuda. A treasure hunter identifies the ampoule as part of a valuable shipment of World War II morphine lost at sea, atop the even greater treasure of a sunken Spanish galleon. Thus begins a race for drugs and treasure pitting Nolte and Bisset against a ruthless drug lord (Louis Gossett Jr.) who'll do anything--even resort to Haitian voodoo--to get what he wants. The movie's best known for Bisset's wet T-shirt scuba-dive, but also has some exciting highlights including a moray eel that attacks on cue and... well, uh, Jacqueline Bisset in a wet T-shirt.

Leviathan / Deep Star Six (both 1989)
-Very similar movies released at close to the same time. Both are
basically "Alien" or "The Thing" set in a deep sea underwater habitat.
Basically, divers disturb or discover some sort of creature that wreaks all sorts of havoc on the habitat and its occupants. A daring escape at the end allows the hero and heroine to survive certain death. In one of the movies a diver tries to escape the habitat without decompressing and suffers an extreme case of "the bends" causing his head to bleed until his body eventually totally explodes.. Hoo-Yah.

The Abyss (1989):
Perhaps one of the most technical underwater movies made that used the largest underwater set of any diving movie to date. Most of us know the story, but here are some cool technical details about the making of the film.
1. All of the underwater scenes in the movie were shot in containment tanks at the abandoned Cherokee Nuclear Power Plant in Gaffney, South Carolina, including the largest underwater set in the world at 7 million gallons (60 feet deep, 200 foot diameter). The tank was filled to a depth of 40 feet, but there was still too much light from the surface, so a giant tarp and billions of tiny black plastic beads were floated on the surface to block the light. During a violent storm the tarp was destroyed, thus shifting production to night time.
2. The water for the tank was fed in from nearby lakes and needed large filters to cleanse it and was chlorinated heavily. This caused many of the actor's hair to become green and even white. The huge quantities of the chemical also caused all the large steel underwater movie props to rust, plugging up the filtering system. For financial reasons, the "Deepcore" set was never dismantled. It stands today in the abandoned (and drained) South Carolina nuclear power plant.
3. The masks were specially designed by Bob Kirby of Kirby Morgan to show a full view of the actors' faces, and had microphones fitted so that dialogue spoken at the time by the actors could be used in the film. The noises made by the regulators in the helmets were erased during sound post-production. Because the diving rigs were not fed by umbilicals, all breathing air had to be supplied via backpack assembly. This being the case, free flow helmets would have been far too wasteful so a demand breathing system was incorporated without oral nasal masks (CO2 build-up anyone?). The tank was equipped with an underwater high pressure manifold with whips so four divers at once could fill their backpacks on the bottom without surfacing.
4. Perhaps the most frequently asked question people ask about the film is in regards to the liquid breathing scene. The Navy has experimented with breathing an oxygen-rich liquid (perfluorocarbon), rather than breathing air. Problems with oxygenation, carbon dioxide removal and lung mechanics prevented this from becoming anything other than experimental.
For the movie, five different rats took five different takes for the liquid breathing scene in the movie. What is seen in the film isn't a special effect. The rat really was subjected to the anxiety of being submerged in this liquid, where it panics and struggles and is then pulled out by its tail as it expels the liquid from its lungs. The rat that actually appeared in the film died of "natural causes" a few weeks before the film opened.

H/Y

What movies get you excited about diving? Comments are welcome!

This Day in Diving History - Treatment Tables 5 and 6 introduced into the U.S. Navy

** This Day in Diving History August 22, 1967 - Treatment Tables 5 and 6 introduced into the U.S. Navy **

The use of oxygen in recompression therapy in the Navy does not go back as far as many believe. In fact, it was not until the 1924 edition of the US Diving Manual that a standard recompression therapy was recommended at all; but these were all air tables. Treatment pressure was based on either the depth of the dive (or a multiple thereof) or the depth of relief, oxygen simply wasn't used back then. It wasn't that no one hadn't thought of using O2 however. The roots of using oxygen as therapy for diving illness can be traced back to Paul Bert's experiments way back in 1870. He first observed that when 100% oxygen on the surface was administered to animals after decompression, some of the signs would resolve. Surprisingly, Bert did not try hyperbaric oxygen, which was first proposed several years later. Initial results were actually disappointing, probably because the therapy was too brief.

In 1939, two US Navy medical officers (Yarbrough and Behnke) first published results of DCS treatment using compressed oxygen, but despite their success, the technique was not initially adopted. Instead for the next 20 years, the US Navy continued to recommend a variety of air tables despite long treatment duration and high failure rates. While these deep air tables provided a higher amount of oxygen, they also caused divers to take up amounts of inert gas in doing so. In the early 1960s, the US Navy instituted another series of investigations into low-pressure oxygen tables. Originally tests used 33 feet as a treatment depth; but due to a high recurrence rate, they were altered to use an initial recompression to 60 feet. This treatment depth not only dramatically improved treatment success, but did so in keeping the risk of oxygen toxicity at an acceptable level - the Navy had found "the sweet spot".

On August 22, 1967, Treatment Tables 5 and 6 were introduced into the U.S. Navy. These treatment tables marked the first time that 100 percent oxygen was used at relatively shallow treatment depths in comparison to the deeper air treatment tables (TT's 1-4). Two additional tables were also introduced (TT-5A and TT-6A) that began with an initial deep short excursion on air followed by treatment profiles identical to tables 5 and 6 (TT-5A was quickly abandoned). Because of the success of low-pressure oxygen treatment of decompression sickness, tables 1-4 are now rarely used. Continued experience with the O2 treatment tables revealed frequent reoccurrences of decompression sickness with the shorter procedures in Tables 5, which now sees limited use for treating diving related illness. TT's 7 and 8 were developed in the 80s to address a longer need for oxygen breathing at 60 feet or deep blow-up respectively; followed by TT-9 in the 90s mostly for non-diving disorders with great success.

Reading: Check out "Diving Medicine" by Alfred A. Bove and Jefferson Davis. This book is commonly referred to as The Bove ('Bo-veigh') and I guarantee that either your friendly neighborhood Master Diver, Diving Medical Officer or Diving Medical Technician has a copy.

H/Y