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Philippines |
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Next Step - Oceanic Phibian |
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Source: The Philippine Diver |
Author: Heneage Mitchell |
Date: 1999-08-24 |
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Back when this writer starting diving, the capillary depth gauge was the standard
by which all other depth sensors were measured. Relying only on a clear plastic
tube filled with air, the exact mid-point of which represents 33 feet (10 metres) of
sea water and Boyles law (?for any gas at a constant temperature, the volume
will vary inversely with the absolute pressure while the density will vary directly
with the absolute pressure?), the trusty capillary gauge accurately reports a
diver?s depth to the maximum sport diving limit of 130 feet. Unfortunately, there
are a few drawbacks. For one, after the 33 foot mark, the gauge becomes
increasingly more difficult to read as the scale reduces logarithmically; for
another, any water trapped in the tube renders it useless. Likewise, a small speck
of sand or even salt left over from a careless rinsing can cause the gauge to
misread. None the less, our instructor (Bill ?Bubbles? Burbridge of Seafari in
Pattaya, Thailand) stressed that the alternative bourdon tube type
gauges were certified ?to within plus or minus 10 feet? and were therefore
nowhere near as accurate as a properly functioning capillary gauge.
My, how times change. Many divers these days wouldn?t dream of diving without
their trusty dive computer lashed to their wrist or tank, faithfully reeling out
depth, time, temperature, tank pressure, adjusted no-decompression times and
decompression stops, SIT data and current maximum bottom times. I think most
divers trained within the last few years wouldn?t know a capillary gauge if it hit
them in the face.
So are you ready for the next step? The micro-processor technology that today?s
dive computer users are so familiar with has come of age in the new Phibian
Closed Circuit System from Oceanic.
Conventional SCUBA breathing apparatus is an Open Circuit System: that is, the
air you exhale is exhausted into the surrounding water. Much of the unused
oxygen which would otherwise have been available to you is thus lost.
Some early underwater breathers used Closed Circuit Systems, such as the World
War ll Navy frogmen whose units delivered pure oxygen which, when exhaled, was
passed through a soda lime ?scrubber? to remove the CO2 and returned to the
system. Some of the drawbacks to these systems included the limitation of a
maximum ?safe? operational depth of 33 feet, as oxygen becomes toxic at a
partial pressure greater than 2 atmospheres and the alarming reaction that
intruding water had on the soda lime scrubber, that of forming an burning, acidic
foam which, upon entering the breathing system, would quickly overwhelm the
diver.
Commercial divers have used closed circuit systems for decades, actually blending
gases to suit the requirements of the depth being worked at the surface and
piping it down to the divers (see SEAFORM CORNER on page...). Until now, this
technology was strictly off-limits to sport divers: Apart from the enormous cost to
set up such a system and the training required to use it, the equipment is so
bulky it requires a fair size tender to accommodate the compressors, gas bottles,
cascade systems, control boards and hoses. Not to mention the recompression
chamber.
Oceanic?s Phibian has changed all that.
Using the same micro-processor based technology that we are all so familiar and
comfortable with in our daily lives, the Phibian CCS 50 NITROX system and the
PHIBIAN CCS100 allows sport divers to easily and safely stay down longer at sport
diving depths and beyond by increasing the amount of oxygen available to the
diver while decreasing the partial pressure of nitrogen in the gas he is breathing,
thereby reducing the risk of decompression sickness. As the gases in the tanks
can be re-used over and over again, the chances of running out of air are slim.
Also, decompession stops, if required, are made shorter and safer by increasing
further the amount of oxygen delivered to the diver.
The CCS 50 has two separate tanks, one containing pressurised air, the other
oxygen. A sophisticated CO2 scrubber removes the exhaled CO2 and returns the
remaining gas to the system. The on-board computer analyses the oxygen
content of the scrubbed air during each breathing cycle and adds the correct
amount of oxygen to the breathing gas mixture to maintain the required partial
pressure of oxygen at any particular depth and workload. The electronic console
offers the same easy to read information as a regular dive computer plus rate of
gas usage on both dilutent and oxygen tanks, oxygen partial pressure status,
sensor conditions and various warning signals. Among the safety features is the
option to attach a standard open circuit SCUBA regulator to the dilutent (air)
tank, redundant sensors and easily accessible manual bypass valves.
The CCS 100 is rated to 100 metres and uses a 4 bottle system to blend a variety
of dilutant mixes including NITROX, heliox and neon oxygen coupled with an
oxygen bottle. Commercial divers will appreciate the umbilical gas support and
bailout system options.
All the components of both systems are mounted within a protective plastic and
fabric shell which is comfortable to wear while affording easy access for cleaning
and routine maintenance.
Oceanic say that a diver can learn to use the new Phibian units with 40 hours of
training, available at authorised Phibian sales outlets (Scubaworld in Manila and
Cebu). The challenge for diver training industry leaders now may be to produce
qualified Phibian instructors in sufficient numbers to capitalise on this new and
exciting advance. Anyone for a PADI Phibian speciality course?
So will this new technology take over from conventional SCUBA? Perhaps not in
the near future, as the price may deter the many sport divers who frequently limit
their diving to occasional vacation expeditions. However, if the right training is
available and enough dive centres are equipped with units for training and rentals,
the benefits of the new Phibian units (and others which are sure to follow) can be
widely understood. If the system performs to its advertised specifications, its
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