guide to buying a wetsuit by Matt Crowther and Steve Warren.
Wetsuits are the most common thermal protection worn by divers.
In water temperatures as cold as 10 or 12 degrees and within commonly
accepted recreational depth and time limits, they perform well.
Unlike drysuits, which offer protection at lower temperatures, wetsuits
do not need to be equalised with compressed air to prevent suit
squeeze. Minor punctures or tears are easily fixed and are not usually
severe enough to stop a day’s diving. Wetsuits cost less to
buy and maintain than drysuit systems. They are also usually lighter
to take travelling.
They perform less well than drysuits as water temperature decreases
and depth increases, as dive times are extended, or repetitive dives
How to avoid the big chill
Water is a powerful conductor of heat, drawing it away from the
diver’s body. If body heat production cannot match the speed
at which the water absorbs it, the diver eventually becomes chilled.
This chilling affects both the ability to think clearly and impairs
control of body functions like dexterity. Wetsuits act only to slow
down heat loss – they cannot replace lost body heat. They
do this in two ways. Firstly, the suit creates a physical barrier
that body heat must cross in order to reach the cooler water outside.
The thicker the suit, the longer this takes and the longer chilling
is delayed. Secondly, they only allow a small quantity of water
to make contact with your body. The more often water enters and
exits the suit, the greater the amount of heat that is used from
the diver’s body to warm it. To combat this, wetsuit designers
try to ensure a close fit that sculpts around the diver’s
body. Special features like seals and waterproof seams and zips
may be used to decrease water flow. Water movement through the suit
is called ‘flushing’.
Making your choice
Three factors should determine your choice of wetsuit: planned
maximum depth, anticipated water temperature (it is usually cooler,
the deeper you dive) and work rate. For example, instructors who
spend long periods stationary while teaching entry-level courses
and are acclimatised to the water temperature will often need a
thicker wetsuit than a holiday diver. Acclimatisation occurs most
obviously for a diver making the transition from cold to warm water
They can allow you to get too warm
We need to remember that as important as it is to avoid getting
cold during the dive, it is also important to avoid overheating
both before and after. A hot and bothered diver is a familiar sight,
and is usually the result of putting on exposure suits a long time
before the dive itself. Dehydration is known to increase the body’s
disposition to decompression sickness, as it significantly affects
a diver’s ability to reduce bubble formation.
Comfort counts if you want to be safe
When buying a wetsuit, a diver must not only consider the correct
choice for the environment but also its comfort and fit and its
relationship to other equipment. An uncomfortable BC/wetsuit combination,
for example, can draw a diver’s attention away from more important
matters such as monitoring dive time and depth. When wearing thin
warm-water suits especially, discomfort often occurs with a ‘hard
pack’ BC. Additional features such as spine pads are worth
looking out for.
WHATS HOT ?
|Not everyone is
a standard size
It is important to have a correct
fit. If it is too loose the suit will be ineffective at minimising
water flow. However, too tight and it will reduce your body’s
blood flow. Both outcomes will result in rapid heat loss. A well-shaped
wetsuit is essential to reducing flushing. It must closely follow
the contours of the human body. A badly-shaped suit will have pockets
of water in it. A combination of stretchier neoprenes, contoured
shaping and a range of sizes means that many – but not all
–people can be accommodated with off-the-peg suits. For those
of a non-standard size, ‘made- to-measure’ suits are
available from most but not all companies. It may take six or more
weeks to deliver a made-to-measure suit. And the suit may need small
final adjustments. It may be worth visiting the manufacturer for
What to Look For
Expanded foam neoprene rubber is used to make wetsuits. Like an
Aero bar, the neoprene is filled with bubbles. The nitrogen bubbles
can be produced by a chemical reaction (chemically blown) or injected
into the neoprene (gas blown). Gas blown is considered to be more
consistent in its production qualities. It is usually more supple.
The gas bubbles are poor conductors of heat. Small bubbles are preferred
as they resist compression better than large bubbles. This further
slows heat loss. Neoprene is available in thicknesses of 1mm to
8mm. Quoted thicknesses for suits are expected to be within 0.5mm.
Neoprene is naturally stretchy when new but as the suit wears out
it loses this property. With repeated use the neoprene bubbles break
down, reducing the suit’s insulating powers and its buoyancy.
Thin, one or two millimetre neoprene vests are an option to keep
core temperatures high. Be careful when layering with thicker neoprene.
Restricted breathing, especially with increased workloads, can cause
shortness of breath, produce carbon dioxide build-up in dead air
spaces and induce panic.
Zips make putting your suit on and taking it off easier, at the
expense of introducing breakage points and increased flushing. Most
suits have entry zips in the front or back. Back zips follow the
contours of the spine and are often easier to remove unaided than
one-piece front-entry models. Zips placed in the forearms and calves
allow the suit to be folded back on warm days to aid cooling. To
prevent corrosion, metal zips of aluminium or brass or nylon or
plastic-coated zips and teeth are used. Backing flaps help to minimise
A few suits incorporate drysuit zips to ensure water cannot escape
Wetsuits are usually glued edge-to-edge and then stitched. Some
suits are flat-locked, which means the edges are cut diagonally
and laid over each other to make a more waterproof join. The main
seams that hold the suit together are usually Mauser, Strobel or
cup stitched. Mauser creates a flat stitch than can be more comfortable
against the skin, but results in needle holes along the seam allowing
in water. Strobel and cup stitches are waterproof and are also used
on drysuits. The thread does not fully penetrate the suit. Cup and
Strobel sewing machines are expensive to buy and as the suit must
often be stitched twice, it is more labour intensive to produce
– obviously reflected in the final price.
Usually suits are nylon-lined, making the suit easy to get on and
off. The lining adds strength, minimising the risk of putting a
thumb through the rubber, and provides a strong surface for the
stitches. Externally the suit may be smoothskin, stippled or faced
with nylon or Lycra. Smoothskin is a plain rubber finish. It minimises
surface area, in turn slowing heat loss, and dries swiftly, inhibiting
windchill. A stippled rubber facing, often called sharkskin, increases
the surface area of the suit and is not so warm. It is more tear
resistant than smoothskin. Nylon linings are slow to dry out of
water, making wind chill a significant factor (a windcheater will
help take the edge off this). They resist abrasion well and are
hard to tear. Lycra linings are very stretchy and faster to dry
than nylon. Both nylon and Lycra suits are easy to dry stitch from
both sides. These suits are called double-lined.
Wetsuits with fitted wrist and ankle seals are known as semi-drys.
Smoothskin cuffs help reduce water movement through the suit. Hoods
often have a smoothskin seal around the face. Some suits have special
seals designed to dock with dedicated gloves and boots.
Suits are available in a range of colours. Team colours can be
used to identify leaders and students, or suit sizes in the rental
locker. Spear fishermen, underwater film-makers and photographers
all have a requirement to get close to marine life and may choose
camouflaged suits. Models for photo shoots may choose high visibility
complementary colours to enhance pictures. Some divers think that
looking different to local prey species may reduce the risk of shark
A snug fit around the torso is most important to slow down core
body heat loss. Remember, most of the body’s vital organs
are situated there.
||Hoods, gloves and boots
Hoods that seal tightly can cause aural barotrauma. This happens when
external pressure is not properly transmitted to the diver’s
outer ear and is similar to wearing ear plugs. Care should be taken
to flood the hood at the beginning of the dive. Hoods can be built
in or separate. Zips that run up to the cheek can restrict head movement.
Separate hoods sometimes have bibs which are meant to divert water
over the top of the suit. If it is tucked into the jacket, cold water
will be channelled into the jacket. Wearing exposure accessories such
as gloves, boots and a hood helps to keep extremities warm and slow
down overall cooling. Remember, around 75 per cent of total body heat
can be lost through the top of your head.
Young divers need to take special care when selecting
a suit system. Their build may require a made-to-measure fitting.
Because they lack physical strength compared to an adult, getting
a suit on and off may be more difficult and require more energy.
Swimming in wetsuits requires energy to move in the restrictive
material and may tire a youngster. It should be noted that children
lose heat faster than adults due to their large surface area to
mass ratio. Purchasing oversized suits to provide ‘growing
room’ is also inadvisable, as is using hand-me-downs that
may have lost much of their insulation.
Finding the right weight
It is important that individuals make an effort
to correctly weight themselves before every dive in a new or unfamiliar
suit. And, as the following results from a pool test reveal, it
is not always easy to guess exactly what effect a different suit
will have on your buoyancy. A two-piece clearly has a very significant
positive effect, but few people would have guessed that the steamer
was neutrally buoyant.
To further illustrate how easy it is is to make
the wrong assumptions about weighting a suit, we asked four experienced
divers to estimate what weights they would have thought necessary
to achieve neutral buoyancy for the same suits. Given that everyone’s
inherent buoyancy varies, this still reveals some serious discrepancies.
Clearly the only way to get your weighting right is to do it in
It is important to remember that all wetsuits will
compress as you descend due to the surrounding water pressure, resulting
in overweighting at depth. The closer you are to neutral buoyancy
at the surface, the less overweight you will be during the dive.