Megalodon vs JJ CCR
Having taught the ISC Megalodon CCR for a number of years, I recently added the JJ-ccr to my teaching curriculum. It wasn’t for long until at least a dozen fellow divers would PM me asking what the best rebreather was.
This posed to be one of the hardest questions I’ve been asked in the last decade. The answer is that they are both as good.
Anyways, if you are facing the dilemma of having to choose, below is a little rundown of the pro’s and cons of each unit.
To take out any means of bias, I also asked two entry level students to swap units once they had completed the Level one car course, so they could give a more ‘virgin’ view of each unit.
Both units are machined out of solid anodised alloy. The can by itself is almost identical in dimensions and so is the scrubber. They both come standard with an axial scrubber, which can be upgraded to a radial scrubber for longer or more demanding dives.
Each unit can be equipped with cylinders of choice. from 2Liter tanks up to 7L tanks is no problem.
They both come with APEKS US4 first stages and the hose routing is almost similar.
Meg and JJ have CE rating, which guarantees that they both withstood serious 3rd party testing, rated to 100m and beyond. I happily stamp both of them as true expedition units and depth well in excess of 200m/600Ft have been dived on them.
Each unit has off board connectors, allowing to add extra gasses in the breathing loop. An array of after market add-on’s allows the heavy techie to expand on the plumbing and electronics plugin.
Setpoints on either unit can be customized above and under water , including an automatic set point and a HUD with Smithers’ code.
Megalodon comes with two independent handsets. and they are truly stand-alone, with independent battery packs. one handset can be upgraded to a shearwater Petrel, allowing on-the-fly deco. The electronics are analog(to mil spec) making it one of the most reliable electronics in the industry
The JJ comes with a shearwater Petrel as a primary handset. It doesn’t have a backup handset, but the new HUD acts as a backup and is also a virtual standalone (own battery supply and processor)
The main difference are the counter lungs. The Meg has standard over-the shoulder counter lungs, where the JJ comes with back mounted counter lungs.
For those of you not familiar; they are exactly what you think; one setup comes over the shoulder in the front and the other ones stay on your back.
The megalodon has a CE approved Bail Out Valve (BOV) which is optional, where the JJ just pulled their BOV out of the market in search for a better performer. There are plenty after market choices on BOV’s.
The meg is quite a compact setup, and once all is in place, you notice the work of breathing; it is good in all positions, even head down. it dives slightly butt heavy and the lungs give clutter in front of your chest. The advantage of having the lungs in front is ease of access. you can plug in off board DIL, oxygen. The ADV is easy to reach or even shut off. The handset is backlit LCD screen and switching set point requires scrolling through the menu.
The JJ is quite large and heavy, mainly because of the stainless steel handle and stand, which makes it very practical to stand up by itself. It is less butt heavy than the meg and the clean chest is very nice.The hoses are neatly tucked away behind the wing and counter lungs.
I did feel slight restriction in the work of breathing in a head down position or in perfect trim. In a slight heads up position, the breathing is as good as the meg. There is only one off board connector (the oxygen has to be disconnected) but the manual addition valve is very nicely designed. Switching set points on the Petrel handset takes 2 seconds and the full colour display is a dream.
Travel was a different story. I tried to get the weight down on the JJ, but still got caught with excess luggage. The meg canister went in my hand carry and I managed to stay within the 24kg of checked in luggage, a big + for traveling divers.
So, I am undecided really. For travel, I would go Meg. for ease of use, I would go JJ. hard working dives I would go Meg. But the clean setup of the JJ is nice and looks good.
Let’s see if the guinea pigs share the same views;
Björn Karlqvist, Swedish, submarine engineer, sidemount instructor;
I really like both. It’s like choosing between a Ferrari or Porsche.
The JJ-CCR is a bit heavier than the Meg on land, but in the water it didn’t make any difference.
JJ-CCR is much easier to dive with than the Meg, especially the first time. Putting it all together and follow the checklist was quite similar with both units. The only distinction, which I think matters the ease of removing the head/ electronics, the Meg is much easier to take apart! JJ’s scrubber is tightly screwed to the head, plus you have to remove all hoses to get it out.
All breathing hose fittings on the JJ-CCR are much easier than the Meg. Especially the T-pieces on the counter lungs are difficult.
Megalodon has chest mounted counter lungs and is therefore much better breathing compared with JJ-ccr ,the JJ has back mounted counter lungs that sit up on the shoulders Lungs. So that’s a big plus for Meg. But allso find the the Meg lungs to be a little in the way.
I whould like to have all free chest like the JJ , to have easy access to d-rings.
What stood out over the Meg with JJ is ADV and manual oxygen add valve.
Meg has the similar valves as on a dry suit and i didn’t like them.
Doing a dill flush on JJ is much easier than on the Meg..
JJ also has a stand from the factory, which makes it stand vertically up. Together with the handle it makes for a very handy unit.
JJ has a shearwater with integrated computer and Meg has an analog handset with LCD backlit screen, and integrated dive computer is optional. So here the JJ wins big time in my eyes.
But Meg has a back-up handset, where JJ doesn’t, which is a downside.
The single LED heads up display on the Meg does the job, but it’s inferior to the HUD on the JJ where you can see all three sensors simultaneously.
The tank adaptors on the JJ are a bit cheap, I didn’t like them at all..
Meg had Quick connects and Really good quallity ones. Overall i Think the Meg looks like its a more well machined piece of equipment.
JJ is allso nice designed but overall not same quality as the Meg.
Whit the Meg you can buy it and build it as you want to have it. Whit the JJ you can not, it comes in a box and ready to dive, which is not my style.
Overall, the JJ was found to be the cleaner, easier unit, with the meg being harder to dive and more clutter but better machined unit. I’ll just keep diving both
David “MOG” Shirley, lawyer and real estate agent
This is not an easy question to answer. I had been researching both units for over a year. My end result, was that I still don’t know. With a keen interest in deep diving requiring helium I needed to make a decision.
While having the opportunity to try dive the JJ, in shallow water with the owner being within 2 metres carefully looking on, I did know that I wanted a re-breather and the JJ was still an option but getting my hands on a MEGALODON in my area proved somewhat difficult.
I did not want to just do a try dive, because let’s face it, most try dives are done in confined water with the maximum depth no greater than a broom stick. This does not represent the diving I do, nor give me the ability to test the unit under the 100’s of different situations and environments that most advanced tech divers find themselves in.
Comparable to taking a car for a test drive around the block but never going on the highway and having to slam the brakes at 60Km per hour, you just don’t know how it is to preform when you need it to. Considering it costs the same amount as the car you buy for your first child, it really is something worth the investigation.
Speaking with instructors that sell or instruct on just one of the units, will still provide you some insight and knowledge. However it is best to take with a grain of salt as they may have a vested interest in selling you their chosen unit.
How did I decide, I spent fourteen days in Thailand diving both units and getting certified on both. I dived both units in various environments and depths. As part of the course I had to perform maintenance, set the unit up each day and carry both pre and post dive checks. Over a fortnight, you get to ask a lot of questions.
What I got out of this fourteen days are both units are fantastic and it not the unit itself which made my decision but the diving I would be doing on it.
I choose the cave meg because it was more suited the diving I was going to do. I have found myself drawn to deep cave diving and wrecks. I plan to travel with my CCR. The Meg had a better work of breathing in all possible positions especially in a heads down position.
I would buy the JJ if I was not going to travel and would not dive in an overhead environment. I found that the MEG was the most suited to advanced technical diving in any environment but slightly harder to use.
Below is short list of advantages and disadvantage I found in both units. Bear in mind the list is composed by someone who only spent two weeks on the unit, and really is a first impression of the units.
Lastly I would like to thank Ben Reymenants form Blue Label diving Thailand for providing the opportunity to dive both units and for the excellent instruction being it in open water, wrecks or caves.
•The Meg needs to have an easier confirm button when change set point on set point controller.
•No stand on the unit rendering it quite unstable in an upright position
•It requires removing the head to turn on and off
•Does not come with decompression computer – But shearwater can be factory added.
•Only one LED on the HUD showing all 3 cells, so you have to count to see which cell is being monitored
•Better work of breathing in any position
•You can fully customise unit– controllers, can size, scrubber, lungs, even after market back mounted counter lungs are available, you can put the unit on just about any wing or back plate
•Redundant System monitor
•Field maintenance and repairs is quite easy
•Lighter than the JJ and smaller
•Easier to perform a diluent flush
•Heavier bulkier unit
•Not really able to customise
•The HUD switch to turn on and off is a bit tricky but I understand this is being replaced free of charge from the manufacturer
•Not much repairs you can do in the field, more like send the head back to manufacturer
•Corrosion can occur where the can meets the stand
•Comes pre- assembled and ready to go, out of the box
•Comes with shearwater controller and computer
•Built in stand and handle
•Three lights on the HUD identify each cell
•Auto calibration without the for a heads only calibration kit
•Easy to dive with, I found better buoyancy and trim