In part 1 of this article we took a closer look at the closed circuit rebreather and how it works in comparison to the conventional open circuit system. Before you opt to try a CCR it is important for a diver to weigh both the advantages and disadvantages of using one.
Advantages of a Rebreather
A Longer Bottom Time
A Closed Circuit diver doesn’t need to worry about running out of gas they are limited only by decompression. This too can be minimized by selecting a partial pressure of oxygen which virtually gives the diver limitless bottom times in 60 feet or less of water.
Silence & No Bubbles
A Fully closed circuit breathing apparatus, discharges no bubbles, making it ideal for underwater photographers/videographers who would otherwise scare away marine life with the constant stream of bubbles. Rebreathers are also used by the Military because of this; they can stealthy move underwater without fear of detection at the surface by the giveaway stream of bubbles.
Gas Efficiency
As the oxygen in the system is re-circulated in the loop, a diver may utilize up to 99% of the Oxygen in the system as opposed to an open circuit system where 20% of the Oxygen is absorbed by the Divers lungs. This creates gas efficiency, with a tank the size of a regular air tank of oxygen lasting ages longer before needing to be changed, limited only by the scrubber.
Deep Diving
A closed circuit rebreather helps in deep diving as a helium system could be easily added to the circuit to eliminate narcosis. The tanks needed for a deep dive are not as many with a rebreather as needed for an open circuit system, allowing the diver greater mobility.
Warm Moist Air
Unlike an open circuit system, the rebreather circulates warm air with more moisture than your ordinary air tank, making it more comfortable to breathe.
Are you ready to switch yet? Do keep in mind that everything isn’t all perfect with a rebreather. They are extremely expensive pieces of scuba diving equipment, require chemical cartridges changes and proper maintenance. There is more that can go wrong with the complexity of the rebreather, and the diver must be aware of scrubbers failing or reaching absorption capacity, or Oxygen toxicity if the controllers fail. Divers need to undergo extensive training to learn to use and manage a rebreather, as so much more can go wrong with one.
Disadvantages of a Rebreather
Initial Expenses
Rebreathers are rather expensive pieces of diving equipment and even the most low range closed circuit rebreathers will cost you way more than your standard open circuit systems.
Ongoing Expenses
After you buy a rebreather, there are still several ongoing expenses in the form of consumables and maintenance. Consumables are those items that are used short term such as; batteries to operate the microprocessors and O2 inject solenoid, scrubber material to remove carbon dioxide, oxygen, air and helium.
Cleaning and Prep Time
Setting up or prepping your CCR is no simple task and requires good training and also needs a bit of time to set up before each dive, to check and cross check if everything is functioning properly.
Discipline & Training
You must have a higher dedication to equipment maintenance and operation than for open-circuit gear. Rebreathers are also generally more complex,which also accounts for why they require more special training time.
Image courtesy: Joi, DeepBlueDiving.gr
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