| Dive International chartered the MY
Coral Queen in the Red Sea and with a group of readers carried out
a series of equipment tests. Each piece of kit was used by four or
five divers, of varying skill levels and physical demands, for at
least five dives - a rigorous trial of 20 to 25 dives with five jurors.
All the divers were observed throughout their dives, completed a detailed
questionnaire and were interviewed afterwards. Their subjective impressions,
coupled with objective research, form the basis of a truly useful
guide to what a piece of equipment is suitable for, and for whom.
The first of our Red Sea Test Team reports is on
the Suunto Favor dive computer.
Suunto is a Finnish company which has specialised in navigational
instrumentation primarily for seafarers for 60 years. It's diving
division is actually an original manufacturer (they don't just sell
someone else's product under their own label) of depth and pressure
gauges, compasses and computers. Suunto's first computer, the SME,
was launched in 1987 and was notable for its small size and innovative
logbook function, which allowed the user to recall dive profiles
in three minute increments without accessories. Ten years on, Suunto
offers a full line of computers that cater for divers wanting no-
decompression or full-decompression facilities, to use air or nitrox,
or requiring gas integration.
The Favor is designed for 'normal' air diving. Because it provides
enough data to plan decompression stops (ie total ascent time) among
its displays, we consider it to be a full decompression computer.
Our Red Sea Test Team test-dived the Favor extensively, making
71 dives and accumulating more than 61 hours bottom time.
Suunto's algorithm, the 'table' that monitors the diver's nitrogen
levels during, between and after dives, has as its basis the same
research that created the US Navy Tables. However, important modifications
have been implemented to take account of more recent research and
make the computer more conservative. For example, 'silent bubbles'
are thought to occur during and after ascents. These bubbles may
not cause problems immediately, but they may remain in the diver's
body for hours or days, and slow down the release of nitrogen. This
is difficult for a table or computer to predict, and repeat dives
only add to the problem by causing more silent bubbles. This increases
the chance of decompression sickness.
Suunto's designers have worked hard to minimise the formation of
silent bubbles in the first place. Suunto uses lower permissable
saturation levels, less 'gassing off' on ascent, and shortened no-stop
times in line with respected research carried out by Dr Merril Spencer.
A 10m/33ft per minute ascent rate is also used to further inhibit
bubble formation (18m/60ft for US Navy tables) and a safety stop
The Suunto also uses longer 'half-times' than the US Navy tables.
Half-times represent the time different body tissues take to absorb
and release nitrogen. The Favor's longest half-time is 320 minutes,
enabling it to consider dives made up to 32 hours apart. Longer
half-times are expected to provide a greater degree of safety for
people diving intensively, such as those making extended decompression
dives, or long repetitive dives over many days typical of liveaboard
divers. The original theory that most tables and computers are based
on, assumed that the body absorbed and released nitrogen at exactly
the same rate. This is now thought to be wrong and Suunto's algorithm
has been modified.
Before you even get to 'Activation' there are no fewer than 15
warnings posted in bold in the instruction booklet. Many of these
are anti-litigation notices (Do not use for decompression, do not
dive below 40m, do not use this computer for half the things it
can do, etc) which are standard issue; others inform the user more
usefully about defensive diving and Suunto should be commended for
including them. Incredibly, there are still divers who think computer
diving is all about strapping on, dropping in and going with the
flow. Dive computers and tables are guides for the intelligent,
not talismans for the uninformed. There's usually plenty of time
to explain how to use them to those who don't know how, when they
are in the decompression chamber.
Our test team checked out the 60-odd page manual for ease of understanding
and gave it 70 per cent. For once, everyone actually read all of
Before diving, the user needs to preset the altitude range from
one of three ranges between sea level and 2400m/8000ft. Suunto recommends
choosing a higher altitude band than needed if the user wants to
introduce a greater degree of conservatism. Wetting the contacts
manually or entering the water prepares the unit for diving. It
isn't possible to dive with the Favor turned off. The computer earned
100 per cent for this safety feature and the fact that it cannot
be accidentally turned off between dives; but only 55per cent when
we asked if it was possible to enter the water with the wrong altitude
setting. In fairness, this would be user error and for sea-level
diving would simply result in reduced dive times.
Our testers awarded the Favor 85 per cent overall for ease of pre-dive