HYPOTHERMIA AND THE HISTORY OF THE EXPOSURE SUIT

Hypothermia has claimed the lives of countless seamen over thousands of years, but the term has become familiar in sea survival only in the past few years. Water transfers heat from the human body 25 times faster than air at the same temperature. In cold water, the heat is removed faster than the body can make it up. The result is that the victim eventually becomes helpless and either drowns or succumbs to the effects of hypothermia itself. It was hypothermia that claimed those who died in the water in the TITANIC disaster. Even though many of those for whom there was no room in the lifeboats did manage to abandon ship successfully in their lifejackets, the frigid water quickly sapped them of their strength.

In 1982, some 70 years later and about 300 nautical miles north of the place where the TITANIC rests off the coast of Newfoundland, some 110 U.S., Canadian, and Soviet men lost their lives to the effects of hypothermia in one night. Bad weather and heavy seas claimed the U.S. drilling rig OCEAN RANGER and the Soviet ship MEKHANIK TARASOV. Thirty or forty of the men on the OCEAN RANGER abandoned ship in a lifeboat that was apparently damaged during launching. This boat capsized alongside a rescue ship. The frigid water rendered the men helpless almost immediately and all of them died just a few feet from rescue. In the case of the MEKHANIK TARASOV, the Soviet sailors apparently waited until their damaged ship was listing too heavily to launch the lifeboats. Only 5 of the 37 on board were saved. Rescuers reported that the survivors were dressed in heavy clothes and were in the water less than ten minutes. Others in the water only a few minutes longer did not survive.

In February 1983, the collier MARINE ELECTRIC sank off the coast of Virginia. There was not enough time to launch the lifeboats and only 3 of the 34 men on board survived the two hours it took for rescuers to pull them out of the 40°F water. Two of these had managed to get themselves out of the water and onto a lifeboat and a liferaft that were floating in the area.

In order to prolong the survival time of those that find themselves in cold water as the result of a casualty at sea, water must be prevented from coming into contact with the survivor's skin and insulation must be provided between the water and the survivor. Attempts to provide this kind of personal hypothermia protection are not new. One of the first efforts may have been a lifesaving suit designed in 1877 by inventor Traugott Beek. The suit was made of heavy canvas and had a hood that could be pulled over the face to protect the wearer from wind and waves. In 1917, the U.S. Navy tested a lifesaving suit at the Brooklyn Navy Yard. Rubber lifesaving suits were being carried on some ships as early as 1927.

During World War II, some U.S. ships on the run to Murmansk carried various types of rubber suits for the crew members. These suits were heavy and

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required a lifejacket to be worn underneath to provide flotation. Although these suits were credited with saving lives, they tended to leak and fill with water. This water diminished the suit's thermal protective value and made it difficult to climb out of the water when rescue arrived. They eventually came

to be considered as dangerous, and in 1943 a special government committee on emergency rescue equipment called for development of a lightweight suit. The approvals of old suits were withdrawn, and the six companies making lifesaving suits began producing them from synthetic rubber. These suits weighed about 6 lb., including the storage bag.

Very near the end of the war, a series of tests was conducted by the Royal Canadian Air Force that resulted in requirements for an aviation exposure suit which was apparently produced for both U.S. and Canadian armed forces. After the war, many of the special wartime safety measures, including exposure suits and lifesaving suits, faded into obscurity.

It took modern materials to make today's exposure suit a practical reality. The materials that made the difference were neoprene and polyvinyl chloride (PVC) foam sheeting that first came into use for diver's wet suits. These materials are closed-cell foams made up of individual air cells, so they float and also provide excellent thermal insulation. With a nylon fabric bonded to each side to protect the foam, these materials were ideal for the application. In the early 1970's, wet suit manufacturers began making "survival suits" for commercial fishermen. This coincided with the growing awareness that hypothermia was a major threat to the lives of survivors of accidents at sea. The lives of hundreds of fishermen have been saved by these suits since their introduction.

REGULATORY HISTORY

In the mid-1970's, studies and experiments conducted in both Canada and the United States indicated that the exposure suit (generally called "survival suit" at the time) could be an effective life-saver. (Appendix I contains a listing of relevant studies conducted in the United States and other countries, as well.) This early work was done as one of the Coast Guard's responsibilities under the Great Lakes Extended Navigation Season Demonstration Program. The work was intended to identify the hazards involved with extending the navigation season further into the winter months, and to develop ways to deal with the hazards. One of the findings was that the hypothermia hazard in the Great Lakes extended well into the normal navigation season, and that many of the deaths in previous Great Lakes casualties were undoubtedly due to the effects of hypothermia. The exposure suit that was gaining wide acceptance among commercial fishermen at this same time appeared to be one very good way to deal with the hypothermia problem.

On April 10, 1980, the Coast Guard published regulations that required exposure suits on large commercial vessels on the Great Lakes (45 FR 24478). On February 3, 1983, just 11 days before the MARINE ELECTRIC tragedy, the Coast Guard proposed regulations to require most large oceangoing cargo vessels, tank vessels, oceanographic vessels, and mobile offshore drilling units to carry the suits for everyone on board (48 FR 4837). The final regulations requiring carriage of exposure suits on these vessels were published on February 7, 1984 (49 FR 4479), and became effective August 6, 1984.

The exposure suit regulations that went into effect on August 6, 1984, paralleled the 1983 Amendments to the 1974 Safety of Life at Sea Convention (SOLAS) in many respects. (SOLAS is an international treaty that originated with the TITANIC disaster, and all major maritime nations are signatories.) The rules require exposure suits for all persons on board oceangoing cargo vessels, tank vessels, oceanographic vessels, and mobile offshore drilling units, and in addition require spare suits for persons on duty in work stations remote from the berthing area where the suits are normally stowed.

Under the regulations, vessels operating exclusively in warm water areas, defined in the regulations as those latitudes between 35° N and 35° S, would not have to carry exposure suits. In this area, water temperature is generally greater than 60°F (15.5°C). The 35 N demarkation line in the U.S. is near Cape Hatteras on the East Coast, and about 40 miles north of the Santa Barbara Channel, near Santa Maria, CA on the West Coast. The exempted area also includes the entire Gulf of Mexico.

Another exemption was provided for vessels with totally enclosed lifeboats with fast and efficient launching devices. The totally enclosed lifeboat arrangement reduces the probability that the crew will find themselves in the water before they have a chance to launch the boat. Once in the water, the boat's enclosure provides protection from hypothermia. One of the purposes of the exemption for vessels with totally enclosed lifeboats was to provide an incentive for shipowners to fit these lifeboats and launching systems, which are superior to presently required systems.

On June 9, 1983, Senators Trible and Stevens introduced S.1441, a bill "to require certain safety equipment on vessels and mobile offshore drilling units, and for other purposes." The major effects of this bill would have been to remove the totally enclosed lifeboat exemption from the Coast Guard rules (still proposed rules at that time), and also to base the warm water exemption on a strict 60° F water temperature criterion, rather than use 60° F only as a guideline.

The major provisions of S.1441 evolved into Sec. 22 of the Coast Guard Authorization Act of 1984 (P.L. 98-557) which in effect directed the Coast Guard to remove the totally enclosed lifeboat exemption from the rules, and to revise the 35° latitude warm water exemption lines to 32° in the Atlantic Ocean.

It also directed the Coast Guard to report to Congress on the effect of changing the warm water exemption line to 31° world-wide. The Coast Guard was to make final regulations effective not later than 60 days after enactment and was to report to Congress not later than 6 months after enactment. President Reagan signed the bill October 30, 1984. The Coast Guard made the revisions to the regulations which were effective December 30, 1984 (49 FR 50722). This report fulfills the requirement for the report to Congress.

SURVIVAL TIME IN COLD WATER

Survival time is the key factor that must be considered in determining what waters should be included in an area where exposure suits should be required. Unfortunately, survival time can not be accurately predicted. Figure 1 appears in the National Search and Rescue Manual used by the Coast Guard, Navy, Army, and Air Force. This figure attempts to define the probability of survival for a certain period of time, as a function of water temperature. Although this figure is probably accurate for a narrow range of human subjects, it will vary widely based on a number of factors. Larger persons can be expected to survive longer than smaller persons. Persons in good physical condition will survive longer than those who are injured or or have certain medical problems. Rough water will make survival more difficult than under calm conditions, and the individual's swimming ability, mental state, the amount of daylight or darkness may all affect survival chances.

A Coast Guard approved exposure suit should extend an individual's cold water survival time by a factor of about seven as compared to survival time in normal work clothes and a life preserver. This figure is subject to a number of complicating factors, but the research data available in several of the reports listed in Appendix I indicate that the factor of seven is reasonable. It must be remembered that the exposure suit may not be significantly better, and may even be worse than a life preserver in preventing drownings in situations where cold water is not the major hazard. Unlike a life preserver, an exposure suit will not automatically turn a helpless wearer face-up in the

water.

In order to completely analyze the effects of moving the warm water exemption boundary to 31°, the validity of the 60° F water temperature guideline should be investigated. In order to do that, the Coast Guard surveyed available marine casualty reports for casualties that involved persons in the water between 50° F and 70° F, without flotation, or with a flotation device that was not an exposure suit. The casualties meeting the criteria and used for this purpose are listed in Appendix II. This survey was complicated by the following factors:

a.

When bodies are recovered, the precise time of death is not or can not be determined.

b. Frequently, some persons are never found, and the reason for death can not be determined.

c. Other factors beside water temperature are often involved, including heavy seas, darkness, and personal injury.

d. Some casualty reports that might be of interest can not be used because some important factor was not recorded, such as sea water temperature, or the length of time persons were in the water.

Nevertheless, figures 2 and 3 were prepared using the available data. These figures represent the 50° F to 70° F portion of figure 1, with the number of hours extended to 12 and over. Figure 2 shows survivors including those with reportable injuries and figure 3 shows deaths. Figures 2 and 3 indicate that figure 1, despite its limitations, is probably a fairly good representation of survival time in the temperature range of interest and can be used for the purposes of this analysis.