DIVERS: Paul (Advanced Open Water, 105 dives logged); Sven (Advanced Open Water, 49 dives logged)
SITE: Coral reef at 50-foot depth with gradual slope to 50 feet
CONDITIONS: 15-foot viz (poor for location), strong current, 81˚F
During the briefing, the divemaster said that there was a ripping current. She told the divers to use the swim line to get to the mooring line, then go hand-over-hand to the bottom, and then swim against the weaker current there. They’d return to the mooring line for the ascent.
“Whatever you do, don’t get behind the boat,” she cautioned. “You’ll drift halfway to Cuba before we can come after you.” Paul and Sven planned to turn back with 1,800 psi.
The current was weaker on the bottom, but the visibility was less than expected. Paul and Sven reached the mooring at 70 feet, and swam an irregular course but generally into the current to stay ahead of the boat, getting slightly shallower. After about 15 minutes, Sven signaled to head back. The current pushed them quickly. They drifted for about five minutes without spotting the line. Paul’s computer showed 76 feet.
Realizing they had probably missed the line, the pair stopped. They both had about 1,500 psi, so Paul signaled to swim into the current until they reached 70 feet, then swim across the current to find the line. After searching for about 10 minutes without success, Sven was down to 600 psi. They had to go up. They surfaced off the boat’s port side, about 100 yards away. Swimming on snorkel across the current as fast as they could, they barely made the trail line, exhausted.
WHAT THEY DID WRONG
They didn’t navigate tightly; Paul had a compass but never used it. Even with topography and current providing general direction references, in the low viz they should have followed a specific course.
WHAT THEY DID RIGHT
They noted their depth was off and stopped. They managed their gas conservatively. Better to wait for a boat pickup than to run out of air underwater.
5 TIPS FROM THIS INCIDENT
1. BE PROFICIENT in compass use and navigation. When low visibility and precise navigation are factors, it’s useful to be trained in these skills. Take the PADI Underwater Navigator course.
2. BE CONSISTENT with compass use. Even when you don’t think you need to — sometimes you’re middive before you realize you need to figure out your bearings.
3. LOOK BEHIND YOU on the first part of your dive. This helps you see how things will look as you head back.
4. TRUST YOUR INSTRUMENTS Your sense of direction is more likely to be inaccurate than your compass.
5. BE READY Even skilled navigators mess up sometimes, so plan for it. In a current, for example, have surface signaling devices so the boat crew can easily spot you if you come up away from the trail line.