Interesting, Dave.
An old Harbor Branch brochure shows what looks to be a CCR-1000 at depth with the caption:
Diver/Scientist at 500' with Closed Circuit Harbor Branch/Bio-Marine Rebreather and Modified Kirby-Morgan Helmet.
I wish I would have owned my Mk 15.5 back when I worked at Harbor Branch. Those guys were (are?) certainly pioneers of deep diving. They had a lot of cool stuff in the day. Now liability is so ridiculous no one is allowed to enter the water from a research vessel without a ream of paperwork. Tim Askew was in charge of operations (including sub ops) at HBOI when I left, and according to HBOI's web site, still is. Anyone talk to him recently about the CCR-1000 origins? Gene Melton from HS Eng would probably know something about that, too.