Reef Oasis Dive Club, Red Sea - Sharm El Sheikh
Reef Oasis Dive Club Dive Sites

Why Rebreather?

Rebreather for All

Think rebreathers are just for technical diving? Think again because the latest rebreathers are lightweight, easy-transportable units that use sophisticated electronics to simplify their use. Rebreathers allow longer no decompression limits, reduced gas consumption and unmatched wildlife encounters.

What is a rebreather?

The primary difference between rebreathers and open-circuit units is that rebreathers reuse some or all of the gas you exhale. There are two basic types of rebreathers: closed-circuit rebreathers (CCRs) and semi-closed rebreathers (SCRs).

why rebreather

Advantages of Rebreathers ?

Efficiency advantages

The main advantage of the rebreather over open circuit breathing equipment is economical use of gas. With open circuit scuba, the entire breath is expelled into the surrounding water when the diver exhales. A breath inhaled from an open circuit scuba system whose cylinders are filled with ordinary air is about 21% oxygen.

When that breath is exhaled back into the surrounding environment, it has an oxygen level in the range of 15 to 16% when the diver is at atmospheric pressure. This leaves the available oxygen utilization at about 25%; the remaining 75% is lost. As the remaining 79% of the breathing gas (mostly nitrogen) is inert, the diver on open-circuit scuba only uses about 5% of his cylinders' contents.

At depth, the advantage of a rebreather is even more marked. The diver's metabolic rate is independent of ambient pressure , and thus the oxygen consumption rate does not change with depth.

The production of carbon dioxide does not change either since it also depends on the metabolic rate. This is a marked difference from open circuit where the amount of gas consumed increases as depth increases since the density of the inhaled gas increases with pressure, and the volume of a breath remains almost unchanged.

why rebreather

Feasibility advantages

Long or deep dives using open circuit scuba equipment may not be feasible as there are limits to the number and weight of diving cylinders the diver can carry. The economy of gas consumption is also useful when the gas mix being breathed contains expensive gases, such as helium. In normal use at constant depth, only oxygen is consumed: small volumes of inert gases are lost during any one dive, due mainly to venting of the gas on ascent. For example, a closed circuit rebreather diver effectively does not use up any diluent gas after reaching the full depth of the dive. On ascent, no diluent is added, however most of the gas in the loop is lost. A very small amount of trimix could therefore last for many dives. It is not uncommon for a 3 litre diluent cylinder to last for eight 40 m dives.

Why rebreather

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