Roger Munns and Jason Isley wearing the rEvo Expedition and Pelagian DCCCR respectively on the lift at Seaventures dive platform

Crossing over from the Pelagian to the rEvo Closed Circuit Rebreather

Roger Munns Blog

I doubt this will interest many people other than rebreather divers so you have been warned!

In late 2016 I decided to evolve from manually operated to hybrid rebreather. It was a tough decision as I have mostly enjoyed diving the Pelagian DCCCR and the investment of time and money in learning to dive a new model is pretty hefty. However I made the switch and six months and 180hrs diving later I thought I’d put down some comments, pros and cons etc.

Why did I decide to make the switch? As I’ve already alluded to this was quite an expensive and time consuming thing to do so it was not a decision I made lightly. There were a few reasons I chose to switch some of which were logistical and financial. The overriding reason though was that, as a cameraman, I believed I would be better served by diving a unit with a solenoid so that I could set my P02 on my computer and let the unit do a lot of the work for me. While I loved (and still love) the Pelagian for many reasons, it is a fully manual rebreather. I’ve had instances where I’ve been very focused on filming and have failed to monitor my gauges for a few minutes so let my PO2 rise or fall significantly. Filming natural history often means I need to be 99% focused on the situation and my camera and trust my dive gear to do its job for a little while.

Loaded and ready to go on location in Japan for Blue Planet II

Loaded and ready to go on location in Japan for Blue Planet II

Once I made the decision to switch I looked around for an instructor. I had two options in SE Asia. Davy Koh in Singapore and Marc Crane in Bali. The costs for each were pretty similar but I preferred Bali as a destination so I went with Marc. Marc is one of the owners and operators of Bali Dive Trek in Amed. It’s about a 2-3hr drive from the airport in Denpasar. It has a really nice setup for tech diving with ample room to tear down and setup gear, a great classroom and a nice deep training pool. It is a little isolated, being a short drive from the small town of Amed, but that suited me as I could dive, eat, sleep and study with no distractions. Diving is accessed by a 10-15min drive to one of the nearby shore dives. The crossover course consisted of three days of theory and training dives and one day of diving. The theory and drills were extensive and it was much more intensive than I had imagined. As you’d expect Marc is a very experienced diver and on top of the course I gained a lot of useful knowledge on dive planning, bailout strategies and tips and tricks for getting the most out of my unit. I would recommend Bali Dive Trek and Marc unreservedly for anyone who is thinking of crossing over to the rEvo or training on it as their first unit.

So after 180hrs underwater what do I like about the rEvo….

Pro’s

  • Well engineered with everything laid out well and hoses etc tidied away.
  • Easy and quick to assemble and disassemble, change scrubber.
  • Excellent scrubber time due to the cycling method.
  • Hybrid – manual or auto options.
  • 5 02 cells mean 3 on shearwater and 2 on rEvo dreams so lots of redundancy.

Cons

  • Gauges and block are a bit chunkier than the Pelagian
  • Heavier than the Pelagian
  • Lungs are locked away in the metal frame so are a little more difficult to rinse or access in the event that they need replacing or repairing
  • Position of counter lungs makes filming in upright positions a little uncomfortable
  • No adjustable bleed valve for 02. I really like that feature of the Pelagian
  • The ADV trigger fires too easily. Luckily I learnt a fix for that but it does seem to be a flaw.

Conclusion

I think that I was a little inexperienced and naive about the differences between diving an ‘automatic’ rebreather and a manual one. The solenoid firing can actually be quite frustrating at times, especially in the shallows where it plays havoc with your buoyancy. I found myself diving the unit manually a lot more than I imagined which negated many of my pre-supposed ideas of the advantages of diving a hybrid unit. What I did find was that there were unexpected advantages like the cycling of the two scrubber units meaning the unit is very economical on sofnolime (an expensive commodity in Asia). Using a shearwater NERD  heads-up display meant I could monitor my P02 without moving my hands from the camera which is a huge advantage for me. The NERD is also available for the Pelagian but can only run off two cells rather than three on the rEvo

I have seen a few other units now and, having had some experience on two rebreather models, I feel that I have a good idea of what to look for now in a rebreather. I can safely say that currently I am very happy with my decision to switch to a rEvo. It’s an amazing tool for my job.