Scuba Equipment

Open-circuit or Aqualung. Using this type of scuba equipment the diver breathes in from the set and out to waste. This type of scuba equipment is usually cheaper and considered more reliable.

Closed-circuit/Semi-closed circuit or Rebreather. Here the diver breathes in from the set, and out back into the set where the exhaled gas is processed to make it fit to breathe again. These existed before the open-circuit sets and still exist today, but are not as popular as the open-circuit sets.

Both types of scuba provide a means of breathing, nearly always from a high pressure diving cylinder, and a harness to strap it to the diver's body. Most open-circuit scuba equipment and some rebreathers have a demand regulator to control the supply of breathing gas. Some divers use the word "scuba" to mean open-circuit sets only.

All modern scuba sets have a spare second-stage demand valve on its own second hose, a configuration called an "octopus" because it often has more hoses for other purposes coming out of the primary regulator on the cylinder top. This second "second-stage" regulator and hose is typically yellow (signaling that it is an emergency or backup device). It is often worn secured into a clip on the stab-jacket or a special friction plug on a diver's chest, easily available to be grabbed by, or offered to, a second diver short of air. Modern "octopus" type primary-stage regulators also typically feature high-pressure ports for use by dive-computer pressure-sensors, and additional ports for additional low-pressure hoses for inflation of drysuits and buoyancy compensator (BC) devices.

Diving cylinder

Air cylinders used for scuba diving come in various sizes and materials and are typically designated by material (aluminum, steel, high-pressure steel, etc). In the US the size is designated by how much air they contain when expanded to 1 atmosphere (80, 100, 120 cubic feet, etc), while in Europe the size is given as their internal volume (10 liter, 12 liter, etc). The most common is the "Aluminum 80", which will give an average experienced diver from 40 to 60 minutes of dive time under common dive conditions.

Air cylinder pressure will vary according to the type of material used, ranging from 200 bar up to 300 bar. Aluminum cylinders are less expensive than steel and have been known to last for 20 years with standard regular maintenance. The drawback is that aluminum cylinders are neutrally buoyant when full, and positively buoyant when nearing empty.

Diving Accessories

In modern scuba sets, a buoyancy compensator (BC) or buoyancy control device (BCD), such as a back-mounted wing or stabilizer jacket (otherwise known as a stab jacket), is built into the scuba set harness. The bladders inside the BCD inflate with air from the ‘direct feed’ to increase the volume of the SCUBA equipment and cause the diver to float. Another button deflates the BCD and decreases the volume of the equipment and causes the diver to sink. The aim of using the BCD, whilst underwater, is to keep the diver neutrally buoyant. The BCD is used to compensate for the compression of a wet suit, and to compensate for the decrease of the diver's mass as the air from the cylinder is breathed away.

In cold water, a diving suit such as a drysuit or a wetsuit. Wetsuits trap a thin layer of water next to your skin. 7mm suits are good for cold water, 5mm suits are igood for the Red Sea and some combination suits will suit most conditions, 3mm suits or less are ideal for the tropics. Dry suits allow divers to remain warm both underwater and on the surface by trapping a layer of air around them.

In very warm water, many types of tough, long, everyday clothing provide protection, as well as purpose made garments such as dive skins and shorty wetsuits

Diving gloves, neoprene is often used for thermal insulation

Diving boots, often made of neoprene and rubber

Diving weighting system - to counteract the buoyancy of the diving suit and diver to allow descent

Scuba Flippers / Fins for efficient propulsion

Compass for underwater navigation

Decompression tables to avoid decompression sickness

Depth gauge is used with watch for decompression monitoring on decompression tables

Distance line is used to navigate back to the start point in poor visibility

Dive Computer to avoid decompression sickness

Watch is used with depth gauge for decompression monitoring on decompression tables

Scuba masks offers clear sight and protection. A Scuba Mask allows the diver to see clearly underwater and protects the eyes.

Full face mask allows talking if no mouthpiece inside.

Diving helmet used with surface supplied diving.

Underwater writing slate and pencil to transport pre-dive plans underwater, to record facts whilst underwater and to aid communication with other divers .

Torch/flashlight is essential in low visibility or dark environments like during night diving, wrecks, caves and for communication.

Diving knife usually with serrated edge for cutting lines and straps, and a blunt tip for prying.

Bags and Luggage including watertight, airtight, dustproof, crush resistant carrying cases

Surface detection aids and Surface Equipment - allow the support boat to monitor and find divers on the surface during or after a dive, prevent the diver being struck by boat traffic and mark the diver's position.

Browse our XTX Packages

Here are some useful books and DVD's available to buy online

Oxygen Measurement For Divers

An Advanced Guide to Digital Underwater Photograph

GPS Afloat

Mastering Rebreathers

Essential Guide to Digital Underwater Photography

International Text Book Of Mixed Gas Diving