HOODS

Hoods are important because they keep your head warm during
diving ... they come in a selection of thicknesses and some
even offer waterproof protection.

SNORKELS

Masks, fins (NOT flippers - Flipper was a dolphin!!!!) and
snorkels are the most basic of diving equipment. Masks allow
divers to see underwater without distortion. Snorkels allow
them to breathe at the surface without having to lift their
heads from the water or use air from their tanks. Fins allow
divers to move through the water with far greater efficiency.

BCDs

A diver's buoyancy control device (or BCD) is used for two
purposes. When inflated on the surface, it allows the diver
to rest or swim comfortably without having to struggle to keep
his head above water. Under water, the BCD may be partially
inflated to offset any decrease in buoyancy caused by compression
of the diver's exposure suit during descent.

SLATES

Diver to diver communication underwater is done using a system
of hand-signals. These signals, however, give only a limited
vocabulary and so as an added way of communicatins slates are used.
These are not, as the name suggests, pieces of stone with a stick
of chalk, but a white piece of plastic with a pencil!

WEIGHTS

Depending on a diver's natural buoyancy and the buoyancy of his
equipment, he may need to use some form of weight system to offset
excess buoyancy. The most common type of weighting is a weight
belt, although there are other options available.

SUITS

Divers require protection from both heat loss and abrasion.
Retaining body heat is of particular importance because water
conducts heat away from the body 20 to 25 times faster than air
of the same temperature. Divers may become dangerously chilled in
water that would seem uncomfortably warm, if it were air.

Thermal and abrasion protection may range from lightweight body
suits for warm-water diving to thick, highly insulated dry-suits
for cold-water diving, like that found around the UK in winter! As
the majority of body heat is lost through the head (about %), a
hood is recommended in cold conditions. Most divers also use some
form of foot and hand protection, such as thick, wetsuit mitts,
lightweight gloves and wetsuit boots - dry suits have integrated
boots.

BOOTS

Wetsuit boots are thick, sock-like items made of wetsuit material
offering thermal and abrasion protection to divers.

FINS

Fins are designed to provide a large surface area to push against the
water, allowing powerful leg muscles to propel you through the water.

KNIVES

Although the risk of becoming entangled underwater is slight,
most experts recommend that all divers equip themselves with
some form of cutting tool. Depending on its design, this tool
may also be used for prying and measuring.

GLOVES

Neoprene gloves protect a diver's hands from abrasion from coral
and other sharp objects, whilst offering thermal protection.

CYLINDERS

Compressed-air cylinders form the heart of any scuba system.
They are designed to be filled with air that has been compressed
and filtered - a process that removes moisture and contaminants and
that allows a volume of air roughly the size of a phone box to be
stored in a space that is a tiny fraction of the size.

Scuba cylinders - most commonly referred to as tanks - enable divers
to remain underwater for up to an hour or so, depending on such factors
as tank size, respiration rate and depth.

GAUGES

The minimal instrumentation with which every diver should be
equipped includes:

• A means of monitoring air supply.
• An accurate means of determining depth.
• A means of measuring the time spent under water.

If a diver does not have a means of measuring depth and time,
then his activities must be monitored by a buddy, divemaster or
instructor who can help keep him within the agreed-upon depth and
time limits. Most experts also recommend that a diver has and uses
an underwater compass. This not only makes it easier for the diver
to navigate, it also helps eliminate the need for long surface swims
at the end of the dive.

ALTERNATE AIR

A cylinder, connected to a two-stage regulator (see
'Primary regulator') is the diver's primary air source.The
most common form of alternate air source is usually referred
to as an 'octupus'. This is an additional regulator second
stage, similar to the one that the diver normally breathes

from. This extra second stage is for sharing with other divers
who may run low on, or out of, air. Another form of alternate air
source is a 'pony bottle', a small scuba cylinder with it's own
first and second stage attached, that is a completely independent
source of air.

REGULATORS

The ability to carry large quantities of compressed air with them
under water is of little value to divers unless they have a means
of reducing this air to ambient pressure. The human respiratory system
is capable of tolerating a pressure differential, between the air being
breathed and the fluid meduim surrounding the lungs, of no more than 2
psi or 0.14 bar.

Breathing is, in fact, difficult if the pressure differential is but a
small fraction of that amount. This explains why divers cannot simply
breathe from a hose or pipe running to the surface. For underwater
breathing to be possible - as well as comfortable - divers require an
air supply that is ambient ie at the same pressure as the water
surrounding them. That is the function of scuba regulator - they take
high pressure air from the cylinder and reduce it to ambient pressure.

Scuba regulators are called 'demand regulators' which means that they
automatically deliver air to the diver 'on demand' upon inhalation.

MASKS

The mask is a vital part of a diver’s gear. It not only protects the eyes
and provides clear sight underwater, but encloses the nose so your ears
can equalize to the pressure as you descend. The single most important
thing is to make sure your mask is watertight. To check this, simply place
your mask on your face, not secured by the strap, and breathe in through
your nose. If the mask stays in place, it is a good fit. If it slips or falls
off, you will need to get a different mask.