From: [email addresss deleted] (ROBBINS, ROB) Date: Thu, 23 Jan 1997 21:14 NZD To: [email addresss deleted] Subject: Antarctic Regs Here is a chart of regulator performance from tests conducted by US Antarctic Program from '89 thru '95. The data was accumulated by Jeff Bozanic and Jim Mastro. All dives were conducted in McMurdo Sound, Antarctica. Water temp range -1.9C to -1.2C. All failures were due to free flow. FFM dives were done in Dry Valley lakes. Water temp 0C. Based on these tests, USAP now issues Maximus regulators. As mentioned earlier, we have had NO failures for past two seasons having made approximately 2000 dives on the regs during that time. Hope the information is of value. Rob Robbins Scientific Diving Coordinator US Antarctic Program Regulator Type # Dives # Failures % Failure Sherwood Maximus 1341 23 1.7% Sherwood Blizzard 2 2 100.0% Poseidon Cyklon 300 710 40 5.6% Poseidon Odin 270 15 5.6% US Divers RAM 259 45 17.4% US Divers Arctic Supreme 7 4 57.1% US Divers Pro Diver 3 2 66.7% US Divers Conshelf Supreme 7 4 57.1% Scubapro Mk10/G200 27 13 48.1% Scubapro Mk10/D350 17 3 17.6% Scubapro Mk200/G200 8 8 100.0% Scubapro Mk10/D400 7 1 14.3% Scubapro Mk10/Polar 6 2 33.3% Scubapro Mk10/G250 1 1 100.0% Dacor Extreme Ice 25 4 16.0% Mares MR-3 2 2 100.0% DSI EXO-26 FFM 106 11 10.4% AGA FFM 12 0 0.0% Totals 2989 178 6.0%From: [email addresss deleted] (ROBBINS, ROB) Date: Fri, 24 Jan 1997 11:46 NZD To: [email addresss deleted] Subject: RE: Antarctic Regs :This is impressive. Is there any consensus on why the Maximus performs so :well? Though I have owned one myself, I would have had no specific reason :to guess that the Maximus would be significantly better than any other in :resisting freezing. We think that the Maximus regs do so well because of the heat transfer plates. There are fins that are in the mouth piece tube that transfer heat from your breath to the second stage valve body. There is also a plate in front of the exhaust valve that also preforms this task. These do a lot. It is also very valuable to be able to turn the air control valve down (or even off) to help control any incipient free flow. :My own diving is in water that is rarely colder than 4.0 - 5.0 C. If I were :diving in sub-freezing water, I would consider using a FMM on *every* dive :that did not require a gas switch. We do not use FFMs for the most part because we are diving under a ceiling and must be able to find the 4' diameter hole. If you DO have a problem -and this used to be pretty common- and have to go to the back-up reg, I don't want to lose my vision too. For most of the season here the vis is several hundred feet and we do not use a tether..... Cheers- Rob Robbins Scientific Diving Coordinator US Antarctic Program