Wednesday, October 28, 2009

** Diving History -- John Scott Haldane "Father of Modern Decompression"....and a bunch of other stuff **




** Diving History -- John Scott Haldane "Father of Modern Decompression".....and a bunch of other stuff **

STAGED DECOMPRESSION
In 1905 shortly after the publication of the first dive manual, British admiralty adopted decompression procedures to depths of up to 180fsw based on British Professor John Scott Haldane's staged decompression theory. Haldane's staged decompression model had a diver leave bottom at a relatively fast rate followed by decompression stops at shallower depths. This was in sharp contrast to continuous-ascent (liner) decompression procedures developed by French physiologist Paul Bert that was being used at that time. Bert's liner decompression model usually recommended a slow but continuous ascent in the area of 3 feet per minute. The problem with liner decompression vs. staged is the very slow/continuous ascent rate which allows the diver to still on-gas while at the deeper depths. While liner decompression works well for saturation type diving (because you cannot possibly on-gas anymore......you are saturated), it posed serious problems for non-saturation type diving.

ACCEPTANCE BY THE U.S.
The U.S. was slow to adopt Professor Haldane's stage decompression procedure, but had great interest. In 1912, George D. Stillson set up a program to test Haldane's diving tables and methods of stage decompression in the Long Island Sound. Prior to these tests, Navy Divers rarely went deeper than 60 fsw. Throughout a three-year period, first diving in tanks ashore and then in open water from the USS WALKE (DD 34), Navy Divers went progressively deeper, eventually reaching 274 fsw (all on air). Before this the believed safe diving limit was 120 feet but these experiments pushed that limit to around 200 feet. Mixed gas diving would not be discovered for another 27 years but would push this depth limitation well beyond that of air.

ASCENT RATES
Haldane's original staged decompression model recommended ascent rates between 5 and 30 feet per minute dependant upon depth. This was later modified to a rate of 25fpm which remained in effect from 1920-1957. Then in 1958, while revising the U.S. Navy Diving Manual, this rate of ascent came under review. Commander Fane of the U.S. Navy West Coast Underwater Demolition Team wanted rates for his frogmen of 100 feet per minute or faster. The hardhat divers, on the other hand, considered this impractical for the heavily suited divers who were used to coming up a line slowly (usually 10 feet per minute). Thus, a compromise was reached at 60 feet per minute, which was also a convenient 1 foot per second for time/record keeping. This 60 feet per minute rate lasted in the Navy from 1957 until 1993, based on this purely empirical decision, with many recreational diving tables and even early computers following suit. In recent years the ascent rate has been slowed to 30 feet per minute as research has shown this rate helped to better guard against illnesses associated with diving such as decompression sickness and gas embolism...it seems Mr. Haldane had it pretty close to start with.

Haldane's basic staged decompression model formed the basis for what all divers (military and civilian) use world wide for non-saturation type diving. Bert's liner decompression procedure became and remains the basis for saturation type diving decompression.

A few other notable FAQ about John Scott Haldane:

1. He was heavily involved in experiments involving the effects of certain gases on the body. One of these gases; Carbon Monoxide affected not only divers but miners and other workers. He was the first to research the effects of CO on the body by breathing it in himself until it saturated his blood, nearly costing him his life. "At the end I could hardly stand and could not walk alone without falling down" he noted. His research revealed the mechanics behind CO poisoning which became known and "the Haldane effect".

2. During the First World War (1914-18) Haldane was asked to identify the type of gas that the Germans had used in the first gas attack of the war. Haldane found it was chlorine. In order to protect the soldiers, Haldane designed the first gas masks, which proved better than the urine-soaked handkerchiefs that the soldiers had used at first. Haldane also demonstrated the value of oxygen in treating soldiers when they were gassed.

3. He introduced the use of small animals for miners to detect dangerous levels poison gases underground, using either mice or canaries. The reason for this (aside from their portability) was that they have a faster metabolism. This faster metabolism causes them to show symptoms of poisoning before gas levels became critical for workers, giving an early warning sign. The use of canaries was used until 1986 when the method was replaced by the electronic gas detector.

4. Haldane led an expedition to Pikes Peak in 1913 to examine the effects of low atmospheric pressure on respiration. His work here also revealed that decompression sickness was not limited only to divers and miners. He also discovered that the respiratory reflex is triggered by an excess of carbon dioxide in the blood rather than a lack of oxygen.

5. Like his experiments involving Carbon Monoxide, Haldane would routinely experiment with toxic and non-toxic gases on his own body. Despite all the benefits these experiments would yield, years of doing them would eventually take its toll on his lungs. John S. Haldane would die of Pneumonia in 1936 and is still remembered as the father of modern decompression theory.

Note: To learn more about John Scott Haldane and his work check out "Suffer and Survive: The Extreme Life of JS Haldane" by Martin Goodman.

H/Y

Thursday, October 15, 2009

** This Day in Diving History -- 15 October 2001 -- Diving operations begin on the Ehime Maru **

February 9, 2001 -- 13:43......about 9 nautical miles off the south coast of Oahu, Hawaii; while conducting an emergency surfacing maneuver, the USS GREENVILLE (SSN-772) collided with the Ehime Maru Japanese fishing vessel. This was part of a demonstration for some civilian visitors, onboard USS GREENVILLE. As the submarine surfaced, it struck Ehime Maru, slicing her hull wide open from starboard to port. Within minutes of the collision, Ehime Maru quickly sank and hit the bottom at 2,000 fsw. A total of 35 people were on board Ehime Maru; 20 crewmembers, 13 students and two teachers. Coast Guard vessels quickly responded and rescued 26 crewmembers. These crewmembers were taken to Oahu for immediate medical treatment, but the remaining nine crewmembers remained missing.
On 16 February 2001, the Supervisor of Salvage and Diving (SUPSALV) and Submarine Development Squadron 5 (SUBDEVRON 5), using the Scorpio remotely piloted underwater vehicle (ROV), located Ehime Maru in 2,000 feet of water. After assessing the technical feasibility and environmental impact of raising Ehime Maru from the ocean bottom, the U.S. government decided to proceed with its recovery. The decision was made not to raise Ehime Maru all the way to the surface but to lift and carry it underwater to a shallow location (115 ft) one mile away from Oahu. Once there, Navy Divers could enter the ship, on 15 October 2001 they did just that. Divers were tasked with five specific mission objectives:
1. Recovery of the 9 mission crewmembers
2. Collection of personal effects

3. Recovery of unique shipboard items
4. Performing hazardous liquids and material removal
5. Rigging the ship for movement to the final relocation site after 1-4 was complete


In order to accomplish this volume of work in a timely manner, divers ran two deep sea dive stations simultaneously. Inside the ship there was sharp metal, destroyed bulkheads, fuel, wire and debris fouling any sort of passage. Despite this and low-to zero visibility, divers located and recovered eight of the nine missing crew members. In the course of searching four of her decks, they also cleared 120 compartments recovering over 2,500 personal and unique shipboard items. A technique called a "hot-tap" was used to drain the ships fuel tanks completely of 45,000 gallons of lube oil and diesel fuel. This prevented any loss of hazardous pollutants to the environment. An estimated two tons of debris would be removed by divers in order to rig the Ehime Maru prior to moving her back out to her final deepwater resting place. After the recovery was complete, on 25 November, Ehime Maru was lifted, towed back out to sea, suspended about 90 feet below the towing barge, and scuttled in over 6,000 feet of water 12 nautical miles south of Oahu where she rests today.
All in all Navy Divers conducted over 650 dives during the course of 29 days. This operation not only gave closure to families and recovered sensitive items but it also only helped avoid future ecological damage due to the fuel. The use of military assets to complete this also went a very long way in public support and U.S./Japanese relations in that it showed genuine concern vice simply throwing money at the problem.

H/Y

Bob Barth - Lowell Thomas Award

For those of you that know Bob and his tendency to be humble............ He was invited to New York by the National Explorers Club to be presented tomorrow with the Lowell Thomas Award for and exceptional live of exploration under the oceans of the world. Bob is not going to be attending. He will however still be the recipient of the prestigious award. We have attached a copy of the video they will be showing at the presentation.


HOOYAH BOB!


video

Tuesday, October 13, 2009

This Day in Navy History -- The Navy's 234th Birthday


The United States Navy traces its origins to the Continental Navy, which the Continental Congress established on 13 October 1775, by authorizing the procurement, fitting out, manning, and dispatch of two armed vessels to cruise in search of munitions ships supplying the British Army in America. The legislation also established a Naval Committee to supervise the work. All together, the Continental Navy numbered some fifty ships over the course of the war, with approximately twenty warships active at its maximum strength.

After the American War for Independence, Congress sold the surviving ships of the Continental Navy and released the seamen and officers. The Constitution of the United States, ratified in 1789, empowered Congress "to provide and maintain a navy." Acting on this authority, Congress ordered the construction and manning of six frigates in 1794, and the War Department administered naval affairs from that year until Congress established the Department of the Navy on 30 April 1798. The Navy would continue to expand and challenge other countries for sea dominance up to World War II. During WWII, the United States become by far the largest Naval power in the world, with over 70% of the world's total numbers and total tonnage of naval vessels of 1,000 tons or greater. Throughout the rest of the 20th century, the United States Navy would maintain a tonnage greater than that of the next 17 largest navies combined.

The Navy's original six frigates were:
1) USS UNITED STATES - Launched on 10 May 1797; decommissioned and placed in reserves in 1849 at Norfolk, Virginia. While in lay-up she was seized and commissioned into the Confederate States Navy, which later scuttled the ship.

2) USS CONSTELLATION - Launched on 7 September 1797. In February 1800, Constellation fought the French frigate La Vengeance and won the first major victory by an American-designed and built warship. After she was struck from service Some timbers were re-used in the building of the second ship to bear the name USS CONSTELLATION.

3) USS CONSTITUTION - Launched on 21 October 1797 and remains the oldest commissioned vessel afloat in the world. The word "afloat" is important because as the HMS Victory lays claim to being the oldest commissioned vessel in the world, she is not seaworthy. Nicknamed "Old Ironsides" because cannonballs of the day could not penetrate her tough oak sides. Today she is still berthed at Charlestown Navy Yard, in Boston, Massachusetts where visitors tour her daily.

4) USS CHESAPEAKE - Launched on 2 December 1799. Served with distinction until 1 June 1813 when she was captured by HMS Shannon and taken into Royal Navy service.

5) USS CONGRESS - Launched on 15 August 1799. During the War of 1812, she captured or assisted in the capture of twenty British merchant ships. Put in reserve in 1813 and served the remainder of her career as a classroom and training ship.

6) USS PRESIDENT - launched on 10 April 1800. In September 1813, USS PRESIDENT captured the schooner HMS Highflyer. Soon thereafter she herself was captured in January 1815 by a Royal Navy squadron. Re-Commissioned as HMS President, she was broken up at Portsmouth, England in 1818.

Characteristics of the original USS CONSTELLATION:

44-gun Frigate with 2,200 tons displacement. Propulsion was by sail (three masts) that could reach a top speed of 13 knots. She berthed 450 officers/enlisted including 55 Marines and 30 boys.

Characteristics of the new Gerald R. Ford class aircraft carriers:
101,600 tons displacement. Propulsion - nuclear (2 reactors) that can reach a top speed of 30+ knots. She will berth 4,660 personnel will come equipped with surface to air missiles, close in weapons systems and will carry more than 75 aircraft.

For those about to rock.....

H/Y

Friday, October 9, 2009

**This Day in Diving History -- October 12, 2000 -- USS COLE (DDG-67) Terrorist Attack**

**This Day in Diving History -- October 12, 2000 -- USS COLE (DDG-67) Terrorist Attack**
Eleven months before the events of September 11, the USS COLE (DDG-67), was on deployment enroute to Bahrain. In need of fuel, the Arleigh-Burke class destroyer entered the harbor of Aden, Yemen for a scheduled refueling. After the mooring of the ship to a buoy, the refueling operation began. Approximately 45 minutes into the refueling (11:18 a.m.), terrorists detonated a small boat packed with explosives on the port side of the ship. The explosion ripped a 1,600 square foot hole in her hull, killed 17 Sailors and left 39 wounded.

In the aftermath of the explosion, the crew of the COLE fought tirelessly to free sailors trapped by the twisted wreckage and limit flooding that threatened to sink their ship. The crew's prompt actions to isolate damaged electrical systems and contain fuel oil ruptures prevented catastrophic fires that could have engulfed the ship and cost the lives of others. Skillful first aid applied by the crew prevented additional deaths and eased the suffering of many others. The crew conducted more than 96 hours of sustained damage control in conditions of extreme heat and stress. Deprived of sleep, food and shelter, they vigilantly battled to save the ship and restore stability to vital engineering systems. This superhuman effort kept the ship afloat although it remained highly unstable. During these efforts, initial hull searches for additional explosive devices on her were carried out by EOD that were deployed in the area. As these initial searches were being conducted, a detachment of Navy Divers was brought on scene and tasked with locating the missing Sailors, ship stabilization, evidence recovery, structural inspections and assistance in loading her on a heavy transport ship that would eventually bring her home.


The first challenge would be to stabilize the ship. The COLE was listing to port, had no electrical power and was still flooding in several compartments. To do this, a surface supplied diving system was set up onboard the COLE which would allow divers to route through multiple decks and compartments for extended periods of time. Diving in enclosed spaces is dangerous enough; adding to this would be diving in a medium of both water and fuel, around shattered bulkheads, buckled decks and a spider web of broken pipes and wires – all in zero visibility with water and air temperatures ranging from 90 to 110 degrees. Once setup was complete, Navy Divers were able to systematically identify, isolate and effectively stop remaining flooding into the ship. In process they recovered several bodies of fallen crew members and successfully stabilized the ship. Once these immediate stability concerns were met, Navy Divers moved to the blast area itself in order to inspect the area, gather evidence and recover remaining crewmember remains.


The blast area on the ship was nothing less than devastating. Noticeable to the world was the immense opening in the hull. Even more disturbing was the level of damage inside the ship. Divers had to be even more careful in this area to ensure they did not cut themselves or their equipment on countless shards of metal. Slowly and methodically, they inspected every inch of the blast area. Through these continued efforts, evidence was gathered about the explosion for investigators and all of the missing COLE Sailors were recovered. These sailors were given full military honors as they were escorted off the ship to begin their long and final journey home.

With the recovery phase completed, inspection dives were conducted so that naval engineers could determine how much of the COLE's structural strength had been lost. The Blue Marlin, a 700-foot-long Norwegian heavy-lift transport ship, was contracted to return the COLE back to the United States. To accommodate the COLE, the Blue Marlin was fitted with special docking blocks that would hold her in the most stable position for the long voyage. The fleet ocean tug USNS Catawba towed the COLE out to deeper waters approximately 23 miles off the coast of Yemen on 29 October. Loading the COLE onto the Blue Marlin required calm seas and a water depth of at least 75 feet. The Blue Marlin partially submerged as tugs maneuvered the COLE into position over the transport's deck. Navy Divers then guided the damaged destroyer into position as the Blue Marlin raised up in the water to meet the ship. The entire docking evolution took almost 24 hours to complete. The Blue Marlin, with the COLE securely held on her deck, began the transit back to the United States.
USS COLE was off-loaded Dec. 13, 2000, in a pre-dredged deep-water facility at the shipyard of Northrop Grumman Ship Systems. After a successful 14-month effort to repair the damage, USS COLE returned to Naval Station Norfolk on April 25, 2002. She would deploy to the Middle East for the first time since the bombing in June 2006. While passing the port city of Aden the crew manned the rails to honor the crewmembers killed in the bombing.

Abd al-Rahim al-Nashiri is alleged to be the mastermind of the USS COLE bombing and other terrorist attacks, who headed al-Qaeda operations in the Persian Gulf and the Gulf states prior to his capture in November 2002 by the CIA. He is currently in American military custody in the Guantanamo Bay detention camp. In December 2008, he was charged before a Guantanamo Military Commission. The charges were dropped in February 2009 pending the Obama administration's review of all Guantánamo detentions, but may be refiled.

H/Y

Monday, October 5, 2009

**This Day in Diving History -- MDSU TWO and SWRMC's Birthday**

**This Day in Diving History October 1, 1966/1986 -- MDSU TWO and SWRMC's Birthday **

Today marks the Birthday of two of Navy Divings major commands, MDSU TWO and SWRMC.

- MDSU TWO -

October 1, 1966 Harbor Clearance Unit TWO commissioned at the Navy Amphibious Base Little Creek, VA.
Patterned after World War II mobile salvage units, HCU TWO consolidated the diving resources of the Atlantic fleet in direct support of combat operations through the clearance of harbors and waterways during the Vietnam War. Along with her sister command (HCU 1), HCU 2 salvaged hundreds of small craft, barges, and downed aircraft; refloated many stranded U. S. Military and merchant vessels; cleared obstructed piers, shipping channels, and bridges; and performed numerous underwater repairs to ships operating in the combat zone.

The command officially became Mobile Diving and Salvage Unit TWO in February of 1982, reflecting the new focus on salvage operations and specialized diving missions. Over the years, MDSU TWO earned the title of "Experts in Salvage" through participation in numerous salvage/recovery operations, harbor clearance, humanitarian operations and battle damage assessment and repair.

The heavy salvage capabilities of MDSU TWO have been demonstrated during such salvage operations as; TWA 800, Swiss Air Flight 111, Space Shuttles Challenger and Columbia and the salvage of USS MONITOR's steam engine, turret, eleven-inch Dahlgren guns and crew remains. MDSU TWO has been involved in quick response battle damage assessment and repair on such vessels as: USS La MOURE COUNTY (LST 1194) and USS COLE (DDG 67). They have also been involved in many humanitarian missions such as Minneapolis Minnesota bridge collapse and the aftermath of Hurricane Katrina. Contributions during the GWOT have included emergent taskings such as the salvage of a SH-60 helicopter in 270 feet of water in the Red Sea and deployments to the Persian Gulf for Operations ENDURING FREEDOM and IRAQI FREEDOM.

MDSU TWO continues to support current and future fleet requirements. The command supports five Mobile Diving and Salvage Detachments (MDSDs), an Unmanned Underwater Vehicle (UUV) Detachment and a Side Scan Sonar team as well as one shore detachment in Norfolk, Virginia. Detachments are trained and equipped with fly-away diving systems and recompression chambers to support the Atlantic Fleet with combat salvage, expeditionary harbor clearance and homeland defense operations.

- SWRMC -

In 1979 COMNAVSURFPAC created a San Diego based Diver Consolidation plan as a pilot program to determine if consolidation of Navy Divers would better effect utilization of diving assets and increase cost savings to the fleet. The first year of the program turned out to be a success and in August of 1980, the unit officially was commissioned as Harbor Clearance Unit One Detachment (HCU ONE DET). The Unit's name was later changed to Mobile Diving and Salvage Unit One Detachment (MDSU ONE DET), when HCU-1 in Hawaii changed its name to MDSU ONE. This should not to be confused with the current MDSU ONE Det ONE Detachment currently in San Diego that would not be reestablished until years later when the Navy saw a need for an asset focused on Salvage/Harbor Clearance on the west coast of the U.S.

The combination of man power and technical expertise at MDSU ONE DET resulted in the development of underwater work procedures for different jobs and classes of ships focusing on UWSH procedures but including some Salvage as well. In addition, MOBDIVSALU ONE DET personnel conducted training aimed at the certification of the Navy's first underwater welders. On October 1, 1986 MOBDIVSALU ONE DET was officially renamed Consolidated Divers Unit (CDU). The command's focus became underwater ships husbandry with the transfer of the salvage portion of the command's mission to MDSU ONE in Hawaii. CDU was again renamed the South West Regional Maintenance Center (SWRMC) Dive Locker on May 22, 2002 and remains one of the Navy's premier underwater ships husbandry assets. Since its inception SWRMC has completed underwater repairs on ships and submarines from bow to stern. They operate not only in the southern California area, but can also conduct fly-away emergent ship/sub repairs. SWRMC also serves at the southwest regions emergent hyperbaric medical facility for all branches of the military. These operations expedite getting the Navy's sea assets back at sea, saving the Navy countless dollars and time in dry-docking costs.

Note: Anyone who has ever walked through the SWRMC Dive Locker has seen the life-sized statue of a diver in full gear, riding atop a 14 foot shark holding its dorsal fin and pointing forward with his other hand. While many have seen this statue, few know the history behind it. The statue was constructed at the Underwater Swim School in Key West, FL by Chief Yeoman Dow Byers. YNC Byers was a UDT Diver who served as an instructor and worked in the carpentry shop. In 1964, he came up with the idea to make a life-sized statue of the school-house's logo - a diver riding a shark. The shark was designed bearing the characteristics of a few sharks; the fine-tooth, mako, sand and nurse shark - and is a female. To create the shark, he shaped pieces of white pine into a skeleton and covered it with fiberglass. The diver was a little trickier. Chief Byers envisioned the diver being tall and thin and searched several dive school classes until settling on one of the instructors to be the model. BM1 Caltenback (a First Class Diver) stood 5'10" and weighed about 150lbs at the time. Byers encased Caltenback in a full body cast from the neck down for four hours during which he protested a great deal and moved not an inch. The result was a life-sized figure of a SCUBA Diver in full gear, astride a 14 foot shark with the words "U.S. Navy School, Underwater Swimmers" in large red letters. Soon after Dow Byers completed the statue, it was displayed at the Monroe County Fair where it won first place ribbons. U.S. Naval School Underwater Swimmers, Key West, Florida, welcomed its first class in 1954 and trained over 6000 divers before officially closing it doors in l973. The statue was then transferred to Navy Dive School, Coronado where it stayed until 1993 when it was transferred once more to CDU (which eventually became SWRMC) where it is proudly displayed to this day.

For more info about the U.S. Naval School Underwater Swimmers, Key West, FL check out http://www.uwss.org/

H/Y