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Equipment Profile
Imagine being 20 minutes into a dive, 120 metres deep, in a cave, and having your breathing system fail! Not only do you need to breathe NOW, you also need to be able to breathe for the next three hours while you do your in-water decompression stops. The diver needs to allow for a second breathing system in case the primary system fails. Amongst rebreather divers there are two schools of thought. One option, and the one that is usually taken, is to either carry extra open circuit cylinders or stage them within the cave. The other option is to wear a second rebreather throughout the dive. If the main rebreather fails, the diver can switch over to the second unit and abort the dive, knowing their gas supplies are still at an optimal mix with a very long duration. Dave Apperley has chosen this second method for his bailout scenarios.
Dave's Twin Inspiration Rebreather |
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Dave has taken a standard Buddy Inspiration rebreather, stripped the guts out, and repackaged it into a custom case along with a complete second loop. The second loop uses standard Inspiration counterlungs, hoses, and mouthpiece, but utilises a custom built scrubber made from PVC. In this photo you can see the two sets of breathing hoses and mouthpieces, and the two sets of counterlungs. Dave is shown adding oxygen to the second system. There is one set of electronics in each unit, and are identified by coloured markings. The red electronics corresponds to the red mouthpiece, and likewise the yellow electronics and mouthpiece. |
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Here is the unit with the rear cover removed. As you can see, the original Inspiration scrubber is upright, slightly higher than the normal position, and the second scrubber is horizontal below it. Flexible rubber hoses connect the second scrubber to the counterlung T-pieces. The internal tanks are the normal three litre steels for the primary loop, and Dave wears side slung tanks for the second loop. |
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In this front view you can see that the unit is reasonably uncluttered, not really much different to the standard Inspiration with the counterlungs over the shoulders. Of course the two side slung cylinders for the second unit are still to be connected, but most Inspiration divers carry at least one of these anyway. The only giveaway in this shot is the second set of hoses and mouthpiece. |
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And here is what makes this setup so neat. The second set of counterlungs are mounted between the casing and Daves back. In this position they are very unobtrusive. You can plainly see the two green oxygen addition buttons, one for each loop. |
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The case was custom built by Rebreather List member Bruce Stewart. It is based on the original housing, but has more internal volume. It was originally made to house a single Inspiration fitted with Faber seven litre steel cylinders so there is still a fair bit of internal space not used. |
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A line up of rigs after a recent 50m wreck dive off Sydney. On the left is Jason's Mk15, next is Dave's twin Inspiration, and on the right is Barry's standard Inspiration. There was also another standard Inspiration on this dive. Note the hinged casing on Barry's unit. |
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Dave climbs back onto the boat after the afore mentioned wreck dive. The unit weighs 46 kilograms so it's not too much trouble to climb the ladder. |
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Last update: January 7, 2002
