You’ll never know how IMPORTANT it is until YOU need IT!
In diving everything is about redundancy, starting at the basic certification of open water diver. We learn that we have an octopus for ourselves in the case of a second stage failure or for our buddy in the case of an out of air emergency. We were also trained to dive with a buddy, perhaps our single largest redundant system. As we progress through the levels we learn the benefits of having a redundant air source (not an air supply system to the same source) in the form of a ‘pony bottle’ or ‘sling tank.’ In technical diving redundancy is a must. All of this training must carry into PSD diving.
As a public safety (PS) diver you are relying on a team to ensure everything goes off without a hitch because there is too much for any one person to manage. Your team is there to back you up and get another diver to you, but in the meantime you need to be prepared to be a team of one and have breathable air. When diving in zero visibility, entanglements can happen and regulator hoses or second stages can rupture or part causing a loss of your primary air.
As we know, there is a diver on the surface ready to render assistance, but it is going to take a few minutes for them to get to you. There are some good arguments on both sides of the issue, should I or shouldn’t I.
- Why should I carry a redundant air supply? It can save me or my buddy’s life. As divers, we are in an aquatic environment and the only reason we can stay there is from the air that we bring.
- Why should I not carry a redundant air supply? We don’t recommend it, but some argue that it is additional equipment, more potential for entanglement and that the diver and tender ‘should’ be able to manage the diver’s air supply.
Here is a situation any PS diver could find themselves in: on tether and close to the end of the line; let’s just use 100 feet (30 metres) for the purposes of this exercise. Let’s now assume something happens, face piece fails or our second stage snags and we tug and it parts. As if this was not bad enough, we try to ascend and find ourselves entangled. So let’s assume this happened right at the beginning of the dive (not sure how we would get to the full length of the tender line) and our cylinder is full but we have no redundant air source. We know it is a low pressure hose that has gone, and we know we are out 100’ (30 metres), and we know we are snagged… so how long will it take us to swim that distance and find the snag?
A test was conducted by Curt Bowen of Advanced Diver Magazine and the results of those tests are below. A low pressure hose that ruptures and is attached to a full 80cf cylinder will drain in 83 seconds. Those results are between 0 and 98 feet (30 metres). Keep in mind that was a full cylinder. So what are the times with less than a full cylinder? I don’t think I want to know. So the question really is, can you swim that distance in 83 seconds – or less?
To sum this up, it does not hurt to carry a redundant air source and it might just save a life. Another point that needs to be made is this: regardless of depth or type of dive, every PS diver should wear a redundant air source on every dive. This makes for a good habit and muscle memory conditioning. The mission is for the whole team to come home safe.
For training on redundant air sources contact your local ERDI instructor. To locate them, visit www.tdisdi.com and click on the ERDI logo.
Contact TDI SDI and ERDI
If you would like more information about redundant air sources or to schedule an appointment with ERDI, please contact:
Tel: 888.778.9073 | 207.729.4201