Suunto HELO2 Scuba Diving Equipment User Manual


 
YOU ARE ADVISED TO MAKE A
DEEPSTOP AT 18 M. THE SECOND
INDICATOR SHOWS THAT YOU HAVE 110
SECONDS LEFT OF YOUR DEEPSTOP.
In order tooptimize the response to different increased risk situations,an additional category
of stop, referred to as a Mandatory Safety Stop, has been introduced. The combination
of stop types depends on the user settings and the specific dive situation.
To get the most from the RGBM safety benefits, refer to Section 10.2. RGBM.
5.3. Emergency ascents
Before youdive, you must havethe dive plancreated with theSuunto Dive Planner printed
out on a slate. You must also have a back-up plan for lost gases. In the unlikely event that
the dive computer malfunctions during a dive, start using an alternative depth gauge and
timer and following the ascent schedule and gas switches that are on the slate. If you dive
using only air, follow these steps:
1.
Assess the situation calmly and then move promptly to less than 18 m/60 ft.
2.
At 18 m/60 ft, slow down your ascent rate to 10 m/33 ft per minute and move to a
depth between 3 and 6 m/10 and 20 ft.
3.
Stay there for as long as your gas supply will safely allow. After reaching the surface,
do not dive for at least 24 hours.
In the event that the dive computer functions but a required gas is not available, you can
use your diving partner's gas, which is set as a secondary gas on the dive computer.
Displayed ASC TIME is not correct, but the decompressions are calculated correctly.
In the event that a required gas is not available at all, decompress for as long as you can
by using the next most suitable gas that has the highest oxygen content. Notice that the
oxygen content should be low enough to not violate the maximum partial pressure of
oxygen (PO
2
).
5.4. Dive computer limitations
While the dive computer's calculations are based on currentdecompression research and
technology, it is important to realize that the computer cannot monitor the actual
physiological functions of anindividual diver. All decompression schedules currentlyknown
to the authors, including the U.S. Navy Tables, are based on theoretical mathematical
models, whichare intended toserve as a guideto reduce theprobability of decompression
illness.
5.5. Mixed gas diving
Diving with gas mixes provides you with an opportunity to increase bottom times, shorten
decompression times, decrease the oxygen partial pressure at depth, and reduce the risk
of nitrogen narcosis or decompression illness by reducing the nitrogen content in the gas
mix.
However, when the gas mix is altered or depth increased, the oxygen partial pressure is
generally increased. This increase exposes the diver to an oxygen toxicity risk not usually
considered in recreational diving. In order to manage this risk, the dive computer tracks
the time and intensity of the oxygen exposure and provides the diver with information to
adjust the dive plan in order to maintain oxygen exposure within reasonably safe limits.
In addition to the physiological effects of enriched air on the body, there are operational
considerations to be addressed when handlingaltered breathing mixes. Elevated concen-
trations of oxygen present a fire or explosion hazard. Consult the manufacturer of your
equipment to check its compatibility with nitrox.
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