Basic HTML Version
D
rysuits have long been standard dress for many
technical divers, underwater photographers,
instructors and other professionals who spend a
lot of time underwater. It’s not surprising then,
that with longer dive times arising from the use of nitrox
and larger capacity cylinders as well as a greater awareness
of the available options, recreational divers are increasingly
choosing to dive dry, even in relatively warm water.
Basics
Drysuits are based on the idea of an inflatable, watertight
shell, which creates a dry envelope around a diver’s body,
combined with insulating undergarments. This two-part
system, invented by British engineer Augustus Siebe in
1837, effectively limits heat loss, which is 25 times greater
in water than on land. The insulating benefits of the system
are especially useful at deeper depths, where compression
of the tiny air pockets in neoprene wetsuits diminishes
their insulating ability. Drysuits are easily adapted to a wide
range of water temperatures; all you have to do is choose
the appropriate thermal undergarments for the water
temperature and your anticipated level of exertion.
Another benefit drysuits offer is improved ability to
maintain neutral buoyancy throughout the water column.
The diver can add gas to the suit using a manual inflator
valve, and excess gas is purged through an exhaust value
positioned near the top of the suit. A drysuit should never be
used as a buoyancy device in place of a BCD; divers should
add just enough gas to the suit to avoid suit squeeze and
make sure to vent excess gas when ascending. Compared to
wetsuits, they generally require more weight to submerge,
depending on the undergarments worn. Like other diving
technologies, drysuits require both training and practice;
most training agencies offer a drysuit course.
The shell Game
Broadly speaking, there are two types of drysuits: shell suits
(also known as membrane suits) and neoprene suits. Shell
suits typically consist of one or more layers of durable fabric
such as polyurethane-coated nylons, vulcanized rubber or
crushed neoprene (neoprene without air cells). Trilaminate
shells are a popular option; these consist of three layers of
material such as nylon, butyl rubber and another layer of
nylon bonded together to form a tough waterproof barrier.
Shell suits, particularly those made with trilaminate, tend
to be lightweight and flexible and can therefore be worn all
day without physically exhausting the diver. They are easier to
don than neoprene suits and dry faster. In addition, because
the shell itself offers minimal thermal protection, the suit is
ideal for diving over a broad range of water temperatures,
from near freezing up to 70 or 75 degrees, depending on the
undergarments used. The trilaminate shell suit is probably the
most popular among technical divers, though many wreck
divers prefer the heavier-duty crushed neoprene.
Foam NeopreNe
Constructed of the same material as wetsuits, older-style foam
neoprene drysuits are typically cut more snugly to reduce drag.
108
|
WINTER 2012
GEAR
Get Wet, Dive Dry
Understanding the basics of drysuit technology
B y M I c h a E l M E N d u N o
S T E P H E N F R I N K
S T E P H E N F R I N K
S T E P H E N F R I N K
108-109_Gear.indd 108
12/22/11