Chapter 37 



ELECTRICALLY HEATED PRESSURE-COMPENSATED 

 WET SUITS FOR SEALAB II 



E. L. Beckman 



Naval Medical Research Institute 



Bethesda, Maryland 



and 



H. R. Frey 



United States Rubber Company 



Wayne, New Jersey 



INTRODUCTION 



Studies on the physiological mechanisms which relate to thermal conservation of the im- 

 mersed diver have been in progress at the Naval Medical Research Institute for several years. 

 At the time of the inception of Sealab n, this laboratory had a contract with the Marine Corps 

 to develop an insulative and supplemental heating garment for thermal protection of Marine 

 reconnaissance swimmers. A prototype garment had been designed and produced on contract 

 and was in the process of being evaluated at the Naval Medical Research Institute. This R&D 

 program served as a basis for the development of the electrically heated, constant-volume, in- 

 sulated garment which was ultimately procured for use by the Sealab 11 aquanauts. As part of 

 this development for the Marine Corps, considerable work had been done to evaluate different 

 types of insulative materials as to their effectiveness as thermal insulators. 



A project was therefore established at the Naval Medical Research Institute by Special 

 Projects May 3, 1965, for the design, development, and procurement of electrically heated, in- 

 sulative undejrwater swimmers wetsuits for Sealab 11 aquanauts. Although this time period was 

 very short for a developmental program, it was considered to be sufficient for the development 

 of a prototype garment for use and evaluation by Sealab n aquanauts, because most of the pre- 

 liminary work had already been done, and the basic concepts of such a garment had already been 

 developed. A contract was let with the U.S. Rubber Company to design and fabricate eight elec- 

 trically heated, insulative, underwater swimmers wetsuits to be powered by either a battery 

 pack or through a cable from a power supply from within the Sealab. The preliminary descrip- 

 tion of the suit requirements defined the duration of the underwater exposure as four hours and 

 the temperature of the water as between 45° and 50° F. These two parameters then defined the 

 amount of thermal insulation required of the suit as well as the number of kilocalories (kcal) of 

 heat to be supplied by the suit to the wearer. With these design limitations, the U.S. Rubber 

 Company's inflatable insulative electrically heated wetsuit was designed and fabricated to fit 

 eight of the personnel who were expected to become the aquanauts of Sealab n (Subsequently it 

 was found that one of the wetsuits fitted two aquanauts). 



Four aquanauts of Team 1 were fitted with the U.S. Rubber Company's electrically heated 

 underwater swimsuit (Figs. 105, 106). Unfortunately, time had not been available to indoctri- 

 nate and train the aquanauts adequately in the use of these garments. Therefore, in several in- 

 stances when the suits were worn by the members of this team, the gas-purging valves were 



Note: The Introduction to this chapter was written by CAPT Beckman; the balance of the chapter 

 written by Mr. Frey, was originally published as the final report for Contract No. 

 N600(168)63855. 



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