(under subclass 185) Method or apparatus wherein the means with which personnel may carry on the underwater operation comprises an underwater enclosure having a gaseous environment in which a specific pressure condition is maintained, and wherein a chamber means is provided having a first sealable opening communicating with said enclosure, and a second sealable opening communicating with the underwater environment, whereby passage of material or personnel into or out of the enclosure can be accomplished while maintaining the pressure condition within the enclosure.
