June 2007    Download the Entire Issue (PDF)

Vol. 22, No. 6     What's this?

NOAA Nixes Split Fins

from the June, 2007 issue of Undercurrent  

The National Oceanic and Atmospheric Administration’s Diving Safety Board issued a report in March recommending new actions for working divers. The major recommendation: Don’t use split fins for diving with heavy loads, in strong currents or when wearing a drysuit.

“They’re fine for light diving or snorkeling but if you’re weighted down or fighting a current, split fins don’t provide the propulsion you need,” says Lieutenant Erik Johnson of the NOAA Diving Center. The report also calls for BCs and DUI weighting systems when diving in drysuits, and limits weight amounts in weight-integrated BCs to 16 pounds maximum.

The report was issued as a response to the USCG Healy incident last August when two Coast Guard divers died during an ice dive near Barrow, Alaska. Jessica Hill and Steven Duque were part of a scientific expedition collecting data but something went wrong after the two plunged into the icy waters through a hole in the ice for a training mission. Autopsy reports reveal the two were 20 feet below the ice when they suddenly descended to nearly 200 feet in a matter of minutes. It would normally take 30 minutes to reach that depth. Duque descended so forcefully that crew on the surface couldn’t hold his safety line to keep him from dropping. When the two were finally pulled up, their tanks were nearly empty. Investigators determined that something pulled them down but could not explain what it was.

In his report to the Department of Homeland Security, Coast Guard Admiral Chad Allen highlighted the fact that the two divers were missing equipment and wearing insufficient or malfunctioning gear. Duque and Hill had on split fins that lacked the power needed to overcome the drag of a drysuit.

Neither wore the required weight belt but instead used integrated weight pockets in their BCs secured by heavy zippers, hard to open for an emergency jettison. They initially entered the water with more than 40 pounds but returned to add more weight and eventually descended with more than 60 pounds of weight, including lead shot and steel tanks. “An over-weighted diver may be able to control his or her buoyancy on the surface, but enter an uncontrolled descent only a few feet from the surface,” Allen writes. He says the amount of weight Duque and Hill used was considered excessive for their body sizes. Experienced divers wearing similar equipment typically use 20 to 30 pounds of weight.

In summary, Allen writes, “It is clear that the divers who lost their lives lacked an adequate combination of training, experience, and judgment to recognize and properly manage the high risk of cold water diving and failed to follow known procedures and regulations.”