Can-Dive Services Ltd., the Canadian subsidiary of Oceaneering International, Inc., working in conjunction with Vickers Oceanics of Edinburgh, Scotland, has developed and successfully applied a closed circuit diver heating system for submersible lockout operations in the North Sea. Following bench and hyperbaric tests to 1,000 FSW, the unit has been installed on the Vickers L-1 submersible. The initial working dive was a 3 hour, 33 minute lockout at 475 feet,

C on the Oxydental Piper A platform. The use of equipment of this type represents a significant breakthrough in providing divers with a safe, reliable heating system when working in situations where there is limited power available. This paper provides a brief outline of some of the problems inherent with closed circuit systems and comments on methods of improving the efficiency of the unit. A list of requirements for an improved distribution garment is also provided.