5 Reasons why we LOVE rebreather diving

By Gary Ward

At Deefer Diving we like to try new things and offer new ways to try diving. This winter we moved into the world of Closed Circuit Rebreather diving. Now diving on rebreathers is not new, the original technology pre-dates regular scuba (by about 80 years!), but with the addition of new technology the equipment is now available for recreational divers.

So what do rebreathers do that makes them so different? The key difference is that the unit does not vent gas into the water after each breath, instead re-using the gas in a breathing loop. To do this the unit must add oxygen into the breathing loop to replace the oxygen your body metabolises, and it must also scrub the carbon dioxide that you have exhaled. This means you are diving with a tank of pure O2 strapped to your bank, but you do take a tank of air (diluent) with you too. With Andre, Matt and Gary now all trained to dive on the rebreathers, we’ve compiled a list of the 5 things we love about rebreather diving.

  1. “Silence is Golden”

The first thing you’ll really notice when diving on a rebreather is the lack of noise. As rebreathers do not vent gas on every exhale, there are less (or no) bubbles bursting forth and rising to the surface. You may not have realised this, but these bubbles and the workings of your regulator make one heck of a din! Switching to a closed loop eliminates this noise and all you will hear is the sound of your breathing in the loop – that is until you discover you can actually talk to your dive buddy!

2. How Much Dive Time?

Open Circuit extended bottom time requires lots of gas

So you’re diving with one tank of pure oxygen and another with air as a diluent. The rebreather unit is adding oxygen to the loop to replace that which you are consuming. That said, you’ve got all the equipment right there on your back to be able to add in a little more O2…. like perhaps mixing Enriched Air Nitrox on the fly. By managing the partial pressure of oxygen at any given depth you can breathe the perfect nitrox blend for the depth that you are diving at. What’s crazy brilliant is that you can mix that perfect blend for the next breath!.

This means that you’re able to extend your bottom times to some incredible numbers, so 300 minutes at 20m (66ft) is infinitely possible, if you have the thermal protection.

3. Warm Moist Gas

There is a thermic reaction going on with the scrubber in the unit needed to eliminate the excess carbon dioxide from the breathing loop. The by-products of this thermic reaction are heat and moisture, which stay in the breathing loop. What does that mean when diving? Well when you’re diving on open circuit scuba you’re breathing highly compressed air. As this air comes through a regulator its cold (have you ever seen the condensation and ice form on a free-flowing valve?). As a diver breathing compressed gas we lose a lot of our core body heat to dealing with this cold gas. With the gas in the loop on a rebreather being warm, we find that we feel warmer in the water, which means we can use some of that extended bottom time more comfortably.

The other by-product is moisture. Have you ever noticed when you come off a scuba dive and you have that dry cotton mouth feeling? That’s caused by the dry air wicking away the moisture in your mouth. On a rebreather, the humidity of the gas you’re breathing is close to 100%, which means you eliminate dry mouth entirely.

4. Close Encounters of the Marine Kind

This is where we cut to the chase on why we really enjoy rebreather diving. Linked to point 1 above (Silence), we don’t make as much noise in the water on a rebreather. This means that we’re able to get much, much closer to the marine life in the water, when they’re doing what they do naturally. Some of the more curious creatures will actually start to approach you as they try to determine what sort of marine life you are…. This simply blows us away on each and every dive!

5. Oh It’s so Cool!

And finally, of course it looks damned cool to have that double hose setup and be the coolest cat on the dive boat. Lots of divers have heard about closed circuit diving, but many have never actually seen it, so is piques a lot of interest on the boat and sparks some great conversations. Its through these interactions with other divers that we’re all able to gain further insight into diving and learn about great new places to dive and ways to dive it. Diving is as much about being with other great divers on the boat, in the shop and in the bar with a cold beer, as it is being in the water….

If you’re interested in learning more about venturing into recreational closed circuit rebreather diving, then head on over to www.deeferdiving.com and fill in the contact details. We’ll come straight back to you with options for getting you started.