Daily Log Report for
5 May 1997

Submitted by Richard Pyle

We spent the morning preparing the two rebreathers we used yesterday, and assembling the rig that John Earle would be using. John made it to Palau this morning, and arrived at the lab around 10 am. Most of the morning and early afternoon was spent tinkering with the rebreathers; particularly assembling the additional twin 30 cubic-foot (c.f.) "offboard" cylinders. Our standard rig configuration includes air as an "onboard" diluent gas supply, and double 30 c.f. "offboard" cylinders filled with Trimix-10/70 (10% oxygen, 70% helium, balance nitrogen). We decided not to join the two 30 c.f. cylinders together, opting instead to regard the left cylinder as the primary offboard gas supply for rebreather diluent, buoyancy compensator inflation, and emergency open-circuit bailout gas; and the right 30 c.f. cylinder serves only as additional open-circuit bailout supply.

We loaded the boat late in the afternoon, and headed for a spot on the reef a few hundred yards north of yesterday's dive site. All started well, with Pat Colin shooting the pictures below. However, when John rolled into the water, he had to immediately abort because his breathing loop flooded. We later determined that I had neglected to replace a small port plug on part of the rebreather, which allowed the loop to flood. Because we didn't bring the tool kit with us today, we didn't have an extra plug to replace the missing one, so John and Pat waited in the boat most of the time while Ken and I did our dive.

Richard Pyle

John Earle

Ken Corben

Tomorrow morning, Ken and John will do some shallow dives for final testing of the rebreathers, and I need to meet with an officer with the Palau Division of Marine Resources to clear our collecting permits. After lunch, we plan to conduct our first "serious" deep dive.

Dive Number 1 of 1
Divers: Richard Pyle, Ken Corben

Solid line indicates depth, dashes ("-") indicate
decompression ceilings, bar ("|") represents cleared to surface.
Max. Depth: 295 feet (88 meters) Time: 5:21pm Duration: 01 hr, 00 min
Location: Augulpelu Reef; E side of reef; vertical drop-off (07 16.41' N, 134 31.43' E)
Marine Life: Similar marine life to what we observed earlier. A fairly robust Grey Reef shark (Carcharhinus amblyrhinchos) followed us down as deep as about 150 feet or so, but never came close. Down deep, near the bottom, I saw a group of Lined Anthias (Pseudanthias fasciatus) and some strange-looking wrasses and gobies. One wrasse of the genus Cirrhilabrus appeared to be a new species, but until I get our collecting permits cleared, I can't start collecting specimens.
Remarks: Water conditions were better than yesterday. I had only got about 4 hours of sleep last night, so I decided to keep the bottom-time short. I stopped just shy of 300 feet, where the coral slope just disappeared into an inky black abyss. The first thermocline was deeper than yesterday; about 150 feet or so. There was a second thermocline just below 200 feet, and another one at 280 feet. Below 280 feet, it was extremely cold - I didn't have a thermometer, but I would guess it was in the low 60's (F). My thin Body Glove wetsuit helped, but my ears and fingers were freezing. I spent less than 10 minutes at depth, and felt as though I could have stayed another 20 minutes or more before the temperature became a problem. We'll try a different locality tomorrow.

Disclaimer: Several aspects of the dive profile(s) illustrated above deviate from conventional wisdom regarding appropriate decompression procedures. The dives referred to on these web pages are of an experimental nature, and all persons involved with these dives are fully cognizant of the associated risks. The decompression practices followed on these dives are derived from published information, in conjunction with the many years of extensive experience of the divers involved. These practices have not been tested under controlled conditions, and may not work equally well for all divers. Kids, don't try this at home!!

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