Rebreathers at Glacier Bay

The USGS Glacier Bay Field Station, in partnership with members of the staff of the NPS Submerged Cultural Resources Unit and Channel Island National Park, is developing a closed-circuit rebreather program.  The objectives of the Glacier Bay Field Station are to enable long-duration dives to map benthic habitats and to undertake detailed observations on  sonic-tagged Pacific halibut, Dungeness crab and Tanner crab to depths of 300 fsw.

Field evaluation of rebreathers occurred in 2000 utilizing the new PRISM rebreathers from Steam Machines to ground-truth sidescan imagery for benthic habitat maps.
 

Photo by Jeff Mondragon Ground-truthing benthic mapping efforts utilizing the Prism rebreather, Farallon diver propulsion vehicle and a progressive-scan digital camera linked to diver communications.  This system allows 2 km transects to 130 feet depth with no decompression obligation.

Peter Readey of Steam Machines coaches the finer points of emergency bailout.

Dave Kushner of Channel Islands National Park making sure all three O2 sensors are recording the same values.

John Brooks of the NPS Submerged Cultural Resources Unit.	Philip N. Hooge of the Glacier Bay Field Station fixing sensors on the Mark 15.5.

A new Scuba Pro full-face mask with communications, modified to enable use with a rebreather, with a switch block to easily change to open circuit bailout.  Mask is designed with an internal airway to avoid C02 buildup at depth, a common problem in other full-face designs for rebreathers. The mask provides a significant safety increase over mouthpieces; it prevents drowning due to convulsions associated with high partial pressures of oxygen, provides quick access to bailout gases, and it enables communication between divers.