It's a diver's nightmare: surfacing miles from shore after a long dive, and finding the boat that brought you there is nowhere in sight.
Hollywood made a movie out of that frightening prospect, and it happened Sunday to two divers off South Florida. Left behind by a commercial dive boat about three miles off Key Biscayne, the divers floated at sea for more than two hours before a passing boat picked them up and brought them to safety just before sundown.
RJ Diving Ventures Inc., the Miami Beach-based boat operator, used a method of accounting for divers that involved standing at the back of the boat as divers returned and checking them off a roster once they were on board, said owner Robert J. Arnove.
"I do not know how the two divers got checked off without them being on the boat or who is to blame,'' he said. "We are still trying to figure that out while devising a further failsafe system to prevent this from ever happening again.''
Leaving divers behind is rare but preventable, dive boat operators said Tuesday.
"I've been in this business for 23 years and I can remember just a couple of occasions of this happening,'' said Matt Stout, owner of Underseas Sports in Fort Lauderdale. "Normally, it's a result of somebody not doing roll call properly.''
Many dive boats perform a verbal call of the divers on board after a dive.
"Usually most boats are very anal about that,'' said Tom Muscatello, owner of the Boynton Beach Dive Center. "I know on our boat, we call names and then we do a head count.''
Arnove said he eliminated verbal roll calls because the wrong person can answer. "This happened to me in Key Largo years ago, and I was left behind,'' he said.
RJ Ventures has been in business since 1982, according to its website. Its 46-foot boat can accommodate about two dozen divers.
On smaller boats with fewer passengers, a missing diver is easier to notice. A simple inventory of air tanks can reveal whether a diver is still in the water.
The divers who were left behind last weekend, Paul Kline of Austin, Texas, and Fernando Garcia Puerta of Spain, had just completed the second of two afternoon dives. They surfaced after nearly an hour underwater only to discover that their boat, the Big Com-Ocean, was gone.
"We were in shock,'' Kline, 44, told The Miami Herald. "We could easily have died.''
The 2003 movie "'Open Water" played on that fear, loosely following the true story of a Louisiana couple stranded by their dive boat in shark-infested waters off Australia's Great Barrier Reef. The husband is eaten by sharks, and the wife, facing a similar fate, chooses drowning. In real life, their bodies were never found and they were presumed dead.
In that case, an inaccurate head count by the dive boat operators was to blame. The U.S. Coast Guard was investigating Sunday's mishap, but so far no official explanation has come out.
"Was a mistake made on the boat? Yes, it was,'' said Sasha Boulanger, owner of South Beach Divers, the shop that signed up the stranded divers for their ill-fated excursion.
"On most trips, we do have one of our employees out there,'' said Boulanger, who has an arrangement with RJ Ventures to take his divers out. "On this particular one, we only had four customers.''
Boulanger said he met with the stranded divers following their rescue.
"We've come out mutually happy,'' he said. "One of the divers is a long-time customer of ours. When he came in, it was hugs.''
The boat captain, Mike Beach, was too distraught to discuss the incident, Arnove said.
"No one else can imagine how awful he feels over this,'' he said. "In 29 years, we have taken out over 250,000 passengers and never had an incident like this occur.''