... Any stories about the Mark II Deep Diving System and SeaLab III?...
There were only 3-4 guys from Sealab III still there by the time I came along. One was our leading Master Diver, Master Chief Chip Hurley. Another was Petty Officer Jay Myers, the youngest Aquanaut on the Sealab III team and the leader in my first sat dive. Chief Cyril Tuckfield was running the dive locker as his last duty station before retirement. Tuck was a legend.
He made the buoyant ascent from 302' from the submarine the USS Archerfish in 1959 with
Captain George F. Bond, the father of
Saturation Diving. His long friendship with Bond lead to his being on all three Sealab projects, either as a support diver or an Aquanaut on Sealab II. I lived in the enlisted quarters across the street from the dive locker and would spend hours talking with him. Aside from being one of the nicest and most modest humans you could ever meet, he would share any bit of knowledge he had accumulated.
The main thing that I learned from all three men was Sealab III was being driven way too fast. If Barry Cannon had not died, others would have. The complexity of jumping from 200' in Sealab II to over 600' for Sealab III was too much for the time available. Both the habitat and the deep dive system were a disaster waiting to happen. The physiology was no problem at all, but the systems were too complex, too untested, and ultimately dangerous.
None of these three men believed that Barry Cannon's death was caused by an empty CO
2 absorbent canister. They knew Paul Wells (the guy who maintained them and was ultimately blamed) too well for that to be true. Several people would have noticed the rig was too light, Cannon would have been too buoyant when he hit the water, and the Mark IX rig performed so poorly that the reduced breathing resistance probably would have been an improvement since the divers had to ride the bypass anyway.
It is amazing that Cannon and Bob Barth didn't pass out and drown from hypothermia on the previous lockouts to fix the habitat. The hot water suits weren't working and I don't think they really understood how much faster heat was lost at 600' than 200'. Washington actually stopped us from making dives to 600' on our way to over 900' in 1972 because we didn't have gas heaters. Fortunately several divers onboard cobbled some heat exchangers together so the Operational Evaluation could continue on the Mark II Deep Dive System.
Some theories included Cannon being electrocuted, or at least shocked. It wouldn't take much of a jolt for a diver in those stressed conditions to pass out or have a cardiac arrest. Even when I was using the very same bells after a massive overhaul, there was still 440 volts inside the bell and the ground fault interrupters tripped on a regular basis.
The Mark II Deep Dive System taught me one of the most important lessons of my career. Backup and safety systems can conspire to make rapid and accurate diagnosis of a problem unlikely. On the Mark II, part of it was poor integration, part poor human factors, and part bureaucracy. We had the time to tame the beast unlike the poor Sealab divers.
Fortunately for me, the semi-closed rigs were retired with Sealab. We just used open-circuit Kirby Morgan KMB-8 Band Masks, steel 72 bailouts, and the early DUI hot water suits. Even then, it was like sucking through a long straw on my deep lockout, but we knew it and could control exertion.
The Mark II DDS had an 850' working depth. We could make excursions in the PTC (Personnel Transfer Capsule or bell) from that saturation holding depth to a little over 1000'. Two more Mark II systems were built for the catamaran submarine rescue vessels, ASR-21 the USS Pigeon and ASR-22 the Ortolan. Both have been scrapped and my old ship, IX-501 the USS Elk River, was sunk in target practice.