By Emilie Voissem, Technical DM
Advantages of Rebreather Diving: Experience the ocean and sea life without bubbles. There are many advantages to diving a closed circuit rebreather, the first one that comes to mind is the lack of bubbles. Another advantage is longer dive times without going into decompression and going deeper with less gas than open circuit.
Bubbles are just noisy to other divers, but they are noisy to the life that we are trying to get close to as well. There is a distinguished difference between open circuit and rebreathers when it comes sea life and how close you can get to them. On open circuit the noise of exhaling gas into the water column will often scare them away. Every time I am on my rebreather and with other rebreather divers I am amazed at how quiet it is. The sea life is not scared and will often come right up to you to investigate further.
Longer dive times without going into decompression is another advantage. When you are diving open circuit you are limited by the gas mix in your tank, and your depth. Your PO2, partial pressure of oxygen, is dependent on both of these factors. When you are on closed circuit you are managing and maximizing your PO2 during the entire dive. By maintaining a constant PO2 no matter what depth you are at, this adds to your overtime bottom time, all without going into decompression.
Another advantage of a rebreather is less gas use on technical dives. For example, doing a dive to 200 feet I will fill a 13cf tank with 100% oxygen and a 13cf tank with a mix of 10/50. I will also bring with me a 40cf tank of 50% and a 40cf tank with a mix of 21/35. The two 40cf tanks will only be used as a last resort if I have a rebreather failure of some sort and have to “bailout”, or also known as switching to open circuit. During the dive I will only be using the gas in the 13cf tanks to operate my rebreather. The cost of this gas is approximately $15.00. The gas in my bailout tanks I will not use and will be able to use the same tanks on other dives. If diving open circuit, doing this same dive you would most likely be on double 80cf tanks for your main gas, “back gas”, with a mix of 18/45. This would cost you about $130. You would also have a 40cf tank of 100% and a 40cf tank of 50%, also at an added cost. Both of the 40cf tanks would be used during your dive to decompress on and would need to be filled every time you do a subsequent dive.
I enjoy the quiet time I have with no bubbles, longer dive times without decompression, using less gas and saving money on my technical dives. These are just 4 reasons on why a rebreather is more advantageous to open circuit in my opinion. If you would like more information regarding rebreathers, please feel free to contact me at firstname.lastname@example.org.