Mobile Saturation Site
Fly-away system restores deep-diving capability to the Navy
By RICHARD R. BURGESS, Managing Editor
Defeating the Bends
Only at the beginning of the project
is a diver required to compress and
only at the end is the diver required
“If you were at 1,000 feet and saturated for longer than 72 hours,
you’re considered saturated with
inert gas,” said Master Chief Diver
Kent Johnson, assigned to the SAT
FADS project with the supervisor of
Diving and Salvage, director of
Ocean Engineering at the Naval Sea
“No matter how long you stay down there, four days
or four weeks, you’ll never take on any more nitrogen
gas,” Johnson said. “Every cell in your body is saturated with that inert gas. As you come up, you’ve got to
come up real, real slow to give your body the chance to
exhale that inert gas from the blood.
“That 1,000-foot dive would take you roughly 11
days to decompress from. The advantage is you could
stay down there for four weeks through six weeks.
Whatever work you needed to do, it always takes you
11 days to get back.”
“[SAT FADS] is designed for deep-ocean salvage and
to assist in submarine recovery [and is] our primary
means to continue to train and operate saturation
divers in the Navy,” said Paul McMurtrie, a retired
master diver and program manager for the SAT FADS
for the supervisor of Diving and Salvage, director of
Ocean Engineering at Naval Sea Systems Command.
Phoenix International is “an underwater operation
company [that conducts] manned diving from
surface-supplied air and mixed-gas diving, saturation
diving and one-atmosphere diving suits, as well as
unmanned remote operated vehicles to 6,000 meters
seawater,” said Chuck Young, the company’s SAT
FADS project manager and a former Navy saturation
The Navy is testing the Saturation Fly-Away Diving System for
future deepwater salvage and submarine rescue use.
■ Tag teams of divers switch off shifts working from a diving bell.
■ Divers live in a decompression chamber after deep dives.
■ The one-of-a-kind system is road- and air-transportable.
The Navy is testing a new, one-of-a-kind mobile diving system that will allow saturation divers to conduct sustained operations 1,000 feet
below sea level, more than three times the current
depth capability. The Saturation Fly-Away Diving
System (SAT FADS) is a multicomponent, manned diving bell system designed to be deployed worldwide to
support organic salvage and recovery operations,
including submarine rescue.
The SAT FADS, which the Navy designed with Phoenix
International of Largo, Md., the ocean engineering firm
that fabricated the system, brings back a deep-diving capability to the Navy that was lost when the submarine rescue
ships USS Ortolan and USS Pigeon were decommissioned
in the 1990s. Their capability was 850 feet.
Saturation diving is a method for conducting sustained operations at great depths while avoiding decompression sickness, also known as the bends. When a
diver is at depth for a long period, the body tissues
absorb the maximum partial pressure of breathing gas
possible — saturation — for that depth. Once saturation
is achieved, further exposure will not result in an
increased time needed for decompression.
Saturation allows divers to work efficiently and economically for weeks at a time without frequent risk of
decompression sickness with repeated dives. After
work periods, the divers live in pressurized chambers
on the diving platform without the need to decompress.