Top Navy Divers Test Advanced Simulator

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Top Navy divers test advanced simulator


ED OFFLEY

Knight Ridder Tribune News Service

It's just another working day in the wet pot. One by one, the four Navy divers strap on their Mark 16 rebreathing rigs, tighten facemasks, check fittings and communications, then step down a metal ladder through a narrow hatch into the 55,000-gallon water-filled chamber that dominates one end of the Navy Experimental Diving Unit building.

Two stories up, Chief Boatswain's Mate Chris Tommasini sits at the dive supervisor's console and orders the exercise to begin. "All stations, three, two, one . . ." he intones into a

The diving unit, known informally as NEDU, is a tenant command at Naval Support Activity-Panama City. Its staff works closely with the Navy Diving and Salvage Training Center and Naval Surface Warfare Center on research and development efforts involving diving gear used not just by the Navy but divers from all of the other military services, said Cmdr. Stephen Reimers, NEDU's commanding officer.

And the massive OSF facility, officials said, is a research and development tool unmatched anywhere else in the world.

Thursday's dive - one of four scheduled over a three-day period this week - is a system check on a new digital electronics system being considered for the Mark 16 rebreathing rig used by Navy Explosive Ordnance Disposal divers, said Navy Chief Tim Nehring, one of the control center staffers. "If this becomes the 'winning candidate' (of three systems being checked out), we will modify all EOD divers' rigs to carry it," Nehring said.

It takes only five minutes for the four divers to reach their exercise depth, where they continue to monitor tiny digital sensors in their facemasks that provide constant readings of the helium-oxygen mixture they are breathing. They also continuously scrawl the instrument readings on plastic tablets with grease pens. After only six minutes pass, Tommasini picks up a telephone handset and orders the four divers to "give me a ready" and he notes four thumbs-up on the monitor screens.

Then it's time to ascend back to sea level. Here, the NEDU divers - like divers everywhere - must adhere strictly to the "tables," the established rules that define the amount of time they must spend decompressing to safely purge the helium gas that the hydrostatic pressure has forced into their body tissues. Nehring gestures toward a wallboard showing a handdrawn "ladder" that defines how long the divers will pause at more than a dozen depth intervals before reaching the surface.

After nearly an hour underwater, most of it spent slowly ascending to the final point just 17 feet down, the divers begin a last decompression pause that lasts 60 minutes.

"This is the hard part," Reimers says with a smile. "It's boring."
Finally, Tommasini orders the chamber depressurized, and the call "seal broke" comes over the intercom. Their black wetsuits glistening with moisture, the four divers emerge from the wet pot, remove the 80-pound diving rigs, and climb up to the upper chambers.

"This is pretty much a typical day for us," says damage controlman1st Class J.R. Hott, one of four divers preparing for the next test.