Rebreather Diving
What is it?
A rebreather is a unit which recycles the gas that you breathe.
One of the problems with scuba diving is that you only have a certain amount of gas that you can breathe. This means that when your gas supply gets low, you must end your dive. However, with a rebreather unit, the gas that you exhale is not released out into the water around you but remains inside a closed breathing loop.
We all learn from an early age that we breathe in oxygen and breathe out carbon dioxide, so let’s look at the rebreather in those terms.
As mentioned earlier, the rebreather is a closed breathing loop. We breathe in our mixed gas with oxygen and breathe out a mixed gas with carbon dioxide. To make that gas safe to breathe again, it is sent through a SCRUBBER unit and a chemical reaction removes the carbon dioxide. Oxygen is then added to the mix, controlled by the rebreather’s electronics and the gas is safe to breathe again.
Megalodon Rebreather
Why Use Rebreathers?
Rebreathers can extend your bottom time, particularly when doing deeper dives. This is due to several factors.
Firstly, as you dive deeper, the ambient pressure (pressure around us) increases. As this happens you will need a greater volume of gas to fill your lungs and therefore, as you exhale, a greater volume of gas is lost to the environment. This is why we use our breathing gas quicker at depth. Closed Circuit rebreathers do not lose gas to the environment so we do not have to worry about depth affecting our breathing rate. Perfect for heavy breathers.
Secondly, Closed Circuit Rebreathers have electronics with sensors that can set the optimum breathing gas mix for you as you dive. For instance, on the megalodon rebreather, you can set your unit to a 1.2 bar PPOxygen which will deliver a 24% nitrox mix at 40 metres, 30% nitrox at 30 metres, 40% nitrox at 20 metres and 60% nitrox at 10 metres. This means you are always getting the optimum breathing mix which will decrease your decompression obligations and give you a margin of safety you don’t get in open circuit diving without carrying lots of different tanks with different mixes.
Another benefit of rebreather diving that is worth mentioning here is the cost of gas. If you are a trimix diver and use a twinset, the cost of getting the right gas mix for your dive can be quite high. Helium is an expensive gas and filling a 12 litre twinset with even a normoxic (20% oxygen) mix can be on the costly side.
However, if you dive trimix on your rebreather, the cylinder you fill is only 3 litres and it goes a long way. So the cost of gas for your deeper trimix dives can be reduced.
For more information regarding rebreathers and our rebreather training courses in Cyprus, please follow the links below or feel free to contact us
