Scuba Diving Equipment - the Completely Equipped Diver

What constitutes the minimum equipment that recreational divers should have and use on every dive? To some degree, this will be a factor of the environment and the purpose of the dive. Divers in cold water require more thermal protection than divers in warm water. Divers engaged in activities, such as underwater photography or night, deep, wreck, ice or cavern diving, require additional specialized diving equipment that sight-seeing divers in shallow, open water may not need.
There is, however, certain equipment items that most experts believe recreational divers should have and use on every dive. The following is a brief overview of each of these items.

Mask, Snorkel and Fins
These are the most basic of all diving equipment. Masks allow divers to see underwater without distortion. Snorkels enable 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 great efficiency.

Exposure Protection
Divers require protection from both heat loss and abrasion. Heat loss 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 wet suits for warm-water diving to thick, highly insulative dry suits for cold water diving. Most divers also use some form of hand and foot protection. Wet suit boots are the most common form of foot protection. Hand protection may range from thick wet-suit mitts or light weight gloves.

Weight Systems
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 general options are available.

Scuba Systems
Modern scuba systems integrate several components, including primary and alternate air sources, buoyancy-control devices (BCD's) and instrumentation.

Air Sources
A diver's primary air source consists of a cylinder of compressed air and a two-stage regulator that reduces this air to the same pressure as the surrounding water. The most common form of alternate air source is an additional regulator second stage, similar to the one the diver normally breathes from. This extra second stage is for sharing with other divers who may run low, or out, of air.

Buoyancy-control Devices
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.

Gauges
The minimal instrumentation with which every diver should be equipped with includes:
a means of monitoring air supply
an accurate means of determining depth
a means of measuring the time spent under water
I would also recommend that each diver have and use an underwater compass. This not only makes it easier for the diver to navigate, it also helps eliminate the need for long, tiring surface swims at the end of a dive.

Knife or Tool
Although the risk of becoming entangled under water is slight, it is recommended 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.

Log Book
Because certification cards only establish that, at one point in time, a diver met the minimum requirements for certification at that level, divers record their dives in log books. Log books provide a tangible record of the depth and breadth of a diver's experience. An increasing number of dive resorts and charter operations require that divers present both certification card and a log book before they will provide diving service.

Slate
The ability to communicate under water using hand signals is limited. So, to convey more-complex messages to one another, divers use specially designed underwater slates.
Using slates may eliminate the need to surface in order to talk and can add the convenience and enjoyment of the dive.