WET SUITS 275 



equipment that hardly satisfies the modern requirements. Emphasis has only recently been 

 put on the need for research, design, and development of equipment that will enable man to 

 operate effectively in the depths along the continental shelves. 



One of the most severe problems facing the modern diver is maintaining the thermal bal- 

 ance of his body is an environment which is essentially a cold and infinite heat sink. A com- 

 parison of the heat capacity and thermal conductivity of water versus air indicates that the 

 subsurface environment is indeed a tough adversary. Body-heat loss is a relatively rapid proc- 

 ess in cold water unless ample thermal protection is afforded the diver. The problem is by no 

 means a new one. It has been with us since the early days of diving. Only the operational re- 

 quirements have changed as diving activities became more diversified. Today, the problem is 

 acute mainly because exposure times have been increased by orders of magnitude. 



fflSTORY 



The need to insulate the human body to reduce heat loss to the water is obvious and has 

 been appreciated for many years. But the supply of heat to supplement the body's heat produc- 

 tion has received very little attention. Electrically heated underwear for surface- supplied 

 helium-oxygen diving was developed during the late 1930' s. Technological problems left much 

 to be desired, and the heated underwear was barely acceptable. Until recently, no attempt was 

 made to provide a heated, insulated garment for other forms of diving and underwater swimming. 



A study of prolonged immersion in cold water has indicated that supplemental heating is 

 essential for thermal balance. Insulation alone will not suffice. The physiological problems, 

 analyses, and recommendations for solutions can be found in reports by Beckman, et. al. [1, 

 2, 3J. 



Evidence to support the concept of supplemental heat in an insulated garment is also given 

 in these reports. The development of heated suits for Sealab 11 was based partly on the argu- 

 ments set forth in CAPT Beckman' s study. 



The development of protective garments for divers and swimmers was not a new one for 

 the U.S. Rubber Company. The history of such work within the company dates back long before 

 the beginning of World War 11. The Clothing Department, part of the Consumer Products Divi- 

 sion, has pioneered the development of various types of diver's and swimmer's dress and has 

 had substantial experience in fabricating such products. Developments were sporadic, however, 

 because interest and funding existed only to solve immediate problems with dispatch. There 

 has been very little long-term research and development by any organization in this field. 

 Prior to the work reported here, the most recent development by the Clothing Plant was a 

 pressure-compensated wet suit for the 432-ft saturation dive made by Stenuit and Lindbergh in 

 1964. The concept of such a suit was established to be worthwhile, even though there were 

 technological problems, of the type that always seem to be associated with an accelerated 

 schedule. 



The Research Center of the U.S. Rubber Company began to examine the problem of cold- 

 water immersion during 1963. New concepts in protective garments were sought. Novel meth- 

 ods for insulating and heating divers were studied. It became apparent that thermal protection 

 for long exposures would require new approaches and modern technology. A team of specialists 

 was formed, drawing on personnel from various departments within the U.S. Rubber Company 

 corporate structure. 



The work reported here is the result of a negotiated contract issued on the basis of "Tech- 

 nical Proposal to Perform Research, Development, and Testing of Electrically Heated Hydro- 

 naut's Suits for Sealab II." The government's request for this proposal followed from a more 

 general and extensive unsolicited U.S. Rubber Company proposal. Much of the groundwork for 

 the heated-suit development was performed in-house prior to the contract. 



