On a recent dive charter in North Carolina with some friends, the DiveMaster asked if someone would team up with a last minute walk on. My buddy and I volunteered. The diver was a local Advanced diver, experienced with 500+ dives and 10 years under her belt. We'll call her Amy.
Over the next 3 days we did 5 awesome dives. The sixth dive on day three went caddy wompus. The wreck sat in 110 feet of water. We were running Nitrox at 30%. MOD 121', NDL 24min. Amy's computer was more conservative, so we agreed to turn the dive when any of us hit 7 min of remaining NDL or 1200 PSI. Me, being larger than my lovely dive buddies, usually turned us on air, Amy turning us on our "Bingo" remaining NDL. We hung out on the wreck around 85 feet with sharks for most of the dive, and about 22 minutes in Amy came over frantically pointing to her computer. It said she was in deco with an 83 minute stop obligation. WHAT? I wrote on my slate "Its wrong". She then pointed to her backup computer...55 minutes of Deco obligation! I checked mine and had 16 minutes until Bingo. I wrote on my slate, " somethings wrong with them"! She then signaled to her air gauge....750psi! I looked at mine and was at 1800 PSI. Then I noticed that she was huffing her reg. I signaled to turn the dive and we headed to the upline. I stayed close to her and gave her my pony bottle when we got on the line. I kept eye contact to let her know I wasn't going anywhere. I also wrote on my slate "Breathe Normal". We hit the safety stop and did three minutes. Then her computers magically went back to normal. WHAT? That's when I noticed her breathing go back to normal.
Back on the boat she was shaken, but unharmed. Her computers, both Zoops, had some sort of sensor issue. Seeing them both in deco put her into a state of narrowed perception affecting her reasoning. She approached me and had already sucked her tank past our agreed turn, which was adding to her stress and increasing her breathing rate even more. We worked the problem out and we made it on the boat safe and sound. It was a freak incident.
Lesson learned? A computer is great, but electronics fail. What would you do if you were alone?
In my OW classes I teach to have a dive plan and a contingency plan. I teach dive tables. Tables are the best solution when your computer goes down. The batteries never run out and they don't require servicing. A timing device, like a watch, and an analog depth gauge are also needed though. No tables? No problem! Go into your computers dive planing mode and write down the deepest planned depth and the next 2 deepest depths and their respective NDL's on your dive slate before you hit the water. You can also do a contingency grid (see pic). Planned depth and time and next two greater depths and times go on the outside, Deco obligations go in the squares. I like to write these on my wrist slate with a sharpie so they wont rub off. I also write bingo times and turn info. They clean up with hand sanitizer or an alcohol wipe.
Hopefully you never have to use them, but its piece of mind.
Over the next 3 days we did 5 awesome dives. The sixth dive on day three went caddy wompus. The wreck sat in 110 feet of water. We were running Nitrox at 30%. MOD 121', NDL 24min. Amy's computer was more conservative, so we agreed to turn the dive when any of us hit 7 min of remaining NDL or 1200 PSI. Me, being larger than my lovely dive buddies, usually turned us on air, Amy turning us on our "Bingo" remaining NDL. We hung out on the wreck around 85 feet with sharks for most of the dive, and about 22 minutes in Amy came over frantically pointing to her computer. It said she was in deco with an 83 minute stop obligation. WHAT? I wrote on my slate "Its wrong". She then pointed to her backup computer...55 minutes of Deco obligation! I checked mine and had 16 minutes until Bingo. I wrote on my slate, " somethings wrong with them"! She then signaled to her air gauge....750psi! I looked at mine and was at 1800 PSI. Then I noticed that she was huffing her reg. I signaled to turn the dive and we headed to the upline. I stayed close to her and gave her my pony bottle when we got on the line. I kept eye contact to let her know I wasn't going anywhere. I also wrote on my slate "Breathe Normal". We hit the safety stop and did three minutes. Then her computers magically went back to normal. WHAT? That's when I noticed her breathing go back to normal.
Back on the boat she was shaken, but unharmed. Her computers, both Zoops, had some sort of sensor issue. Seeing them both in deco put her into a state of narrowed perception affecting her reasoning. She approached me and had already sucked her tank past our agreed turn, which was adding to her stress and increasing her breathing rate even more. We worked the problem out and we made it on the boat safe and sound. It was a freak incident.
Lesson learned? A computer is great, but electronics fail. What would you do if you were alone?
In my OW classes I teach to have a dive plan and a contingency plan. I teach dive tables. Tables are the best solution when your computer goes down. The batteries never run out and they don't require servicing. A timing device, like a watch, and an analog depth gauge are also needed though. No tables? No problem! Go into your computers dive planing mode and write down the deepest planned depth and the next 2 deepest depths and their respective NDL's on your dive slate before you hit the water. You can also do a contingency grid (see pic). Planned depth and time and next two greater depths and times go on the outside, Deco obligations go in the squares. I like to write these on my wrist slate with a sharpie so they wont rub off. I also write bingo times and turn info. They clean up with hand sanitizer or an alcohol wipe.
Hopefully you never have to use them, but its piece of mind.
