Scott Hydro Pak
Scott Aviation Corporation of Lancaster, New York,
was founded by Earle M. Scott in 1932, remains the oldest company
in the U.S. to have designed and produced scuba units.
The Scott Hydro-Pak fullface mask scuba featured
innovations that included a single hose regulator, a tilt valve
second stage and purge button, a snorkel/surface vent system and a
regulated exhaust valve.
The first stage regulator featured a manual reserve system and
the tank harness featured a cam actuated tank band and a breakaway
The Patent (Inventor: Charles D. Cupp) relates to a breathing apparatus which can be used either above or below the surface of the water, but relates more particularly to an underwater, breathing apparatus of the demand type which is portable and self-contained and employs compressed air as the inhaled breathing fluid, with the exhaled, foul air being discharged through an exhalation valve into the ambient medium.
Some of these features were borrowed from Scott's
The Scott Hydro Pack was called the
"Cadillac" of diving lungs. A 1958 Scott Hydro-Pak was
sold for $250.00 while a comparable Northill Air-Lung was sold for
The full face mask with 5 1/2" safety gass
lens was made of natural rubber. It gave easy, natural breathing
in any position. Supplies all the air "demanded" om
inhalation, stops during exhalation. Its placement on the side of
the face opposite the exhalation valve provides the proper
pressure balance for perfect comfort and prevents accumulation of
The Scott Demand Regulator adjusts to the diver
and the water depths automatically. All metal regulators parts
were stainless steel for corrosion protection. It is designed to
open easily for cleaning and inspection. The exhalation valve
assures fine breathing-cycle balance and the exhalated air does
not interfere with vision.
There is a water ejector button to eliminate the
water from mask. To operate it you just lift edge of mask under
chin and press button at the same time. The "Air
Econo-miser" is for conserving air supply while diver's head
is out of water. It permits breathing surrounding atmosphere air.
To operate it, the diver just turns valve at top. When the
"Air Econo-miser" is open, the demand regulator will not
operate out of water.
There is a Reserve Air Supply Valve. See that pointer is in indentation before entering water. When air supply diminishes to remaining 1/4 tank, increased breathing resistance is the signal for diver to turn on the air reserve valve, thereby making the last 1/4 of the air suplly availabe for use.
The Hydro-Pak's first stage is a spring and diaphragm
actuated upstream valve regulator set to the intermediate stage pressure of 100 P.S.I..
Scott features three basic first stages. The first was a single tank unit, with reserve, that bolted directly to the tank
valve with a nipple adapter. The second was a dual tank unit,
identical to the single, with two opposing nipple adapters that connect it between the tank valves. Finally, the Navy
units, short versions of the Hydro-Pak units minus the reserve system that featured a yoke and wing bolt assembly to
fit standard Scuba post valves.
After testing the Air-Pak underwater, the Royal Canadian Navy asked Scott to design
a scuba based on that unit in 1950. The Hydro-Pak was delivered to the
U.S. Navy in late 1952 and reached civilian markets by early 1953. Scott
ended production in the 1961-62 era.
SCUBA WORKSHOP - EDUCATION
THROUGH PRESERVATION - Dedicated to the preservation and
restoration of our scuba equipment heritage. - by
Kent Rockwell - Historical Diver Vol. 9 Issue 3 Summer
Hydro Pak Operation Instruction.