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April 2019    Download the Entire Issue (PDF) Available to the Public Vol. 45, No. 4   RSS Feed for Undercurrent Issues
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Old Dive Computers, Odd Treatment: Letters to the Editor

from the April, 2019 issue of Undercurrent   Subscribe Now

David Hollabaugh (Fulton, MO) wrote in to disagree with John Bantin's article, "Is Your Old Dive Computer Still Safe?" in last month's issue.

"I am a 66-year-old male, diving since 1975, with 473 dives logged. I have done 269 of those dives on an Orca Marathon computer since 1994, most recently in January. The Marathon uses a modified Haldanean algorithm. In your article, you asked, 'Can it be set for nitrox?' No, but I don't use nitrox. 'Does it allow you to set degrees of caution?' No, I set my own, i.e., I don't use at high altitude, I never get closer than five minutes to required decompression, I always make a safety stop, and I do not begin a repetitive dive until I have at least 45 minutes available at 60 feet. 'Does it tell you how long your air will last?' No, I use my pressure gauge. 'Can you read and understand the display easily?' Yes. The battery is user-replaceable, although I am still on the original battery after more than 24 years."

"One thing I don't like about the Marathon is that prior dives are not retrievable once you begin a repetitive dive, so you must note your depth and bottom time between dives if that is important to you. My wife and four friends also continue to use their Orca Marathons with no issues. In any case, computer divers should have a backup plan using dive tables in the event of computer failure to manage ascents and subsequent repetitive dives and avoid waiting a day or longer to dive again."

John Bantin answers, "The original battery after more than 24 years? You've discovered some technical magic there. After more than 7,000 dives, I've been lucky enough to say I've never had a computer fail during a dive, including those with significant deco stops, but that doesn't dissuade me from always taking a second one with the same algorithm as a back-up. In the final analysis, it's whatever works for you."

Canada's Odd Protocol on Hyperbaric Treatment

Daniel Vale (Bowmanville, Ontario) says that reading last month's article, "Bad Stories about the Bends," specifically the hyperbaric chamber director's dispute with the local hospital, brought to mind a similar episode for him. "Some years ago, when teaching a group of high school students in a large swimming pool, another instructor had a student get away from him on an air-share drill and bolt to the surface. The student had chest pain, labored breathing, pain in his right eye socket, and tingling in his left hand.

The 911 on-call physician insisted he had to go to the nearest hospital for evaluation, rather than direct to the hyperbaric center at Toronto General Hospital. I had some difficulty getting the emergency physicians there to listen to my concerns, and they appeared a bit put off by my review of diving physics as they relate to pulmonary overinflation syndrome. However, the student was eventually treated at Toronto General Hospital and made a full recovery. Coincidentally, the latest edition of the Red Cross's Emergency Medical Response course has reasonably detailed information on scuba-related injuries."

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