Building a Sidewinder / Gemini rebreather clone

I suppose I should start this post off with a bit of a disclaimer. Rebreathers are dangerous and can kill you without proper training, discipline and understanding. Don’t build or modify a rebreather unless you have a proper understanding of all the concepts behind everything you’re doing, even then things can still go wrong. Always know your ppO2. If you’re not sure or something doesnt feel right then there is no harm in bailing out. Plenty of really smart (and unquestionably stupid) people have died because they thought they knew better.

With that said, back to our regularly scheduled programming. I’ve wanted to get a sidemount rebreather for a while. It would be incredibly useful for some of the Mexico cave diving and exploration that I’ve been doing the past couple years. Also to be blatantly honest, I just like new shiny things and I wanted to tinker. Mostly I just wanted it for one particular Mexican cave.

Which unit to get?

I have friends with Sidewinders, Sidekicks, Kisscats, Choptimas, Tritons, Geminis, and they all tell me to get the unit that they have. They all swear they are the best units out there; nobody makes a better rebreather. The bee’s knees, as they say (I’ve literally never used that phrase in my life). I don’t pretend to an expert here but I’ve owned and trained on 3 different rebreathers. Without embellishing any numbers I’ve got well over 1500 hours on a the loop. Some might consider that a lot of hours while others would just laugh and tell me to keep counting.

What I do know is there is no “best” unit however most people are fiercely loyal to the rebreather brand they own or instruct on. Almost every mainstream rebreather has it’s own rabid fanatical fanbase but the truth is most of the commercial units out there all do the same thing. Some have different features but the fundamentals are largely the same. You breath into a bag (counterlung) and a CO2 scrubber “cleans” the gas and then you add O2 and diluent to make the gas volume. Some are electronically controlled, some are manual, some have 3 cells some have 6 cells. You get the point. None of this is revolutionary or groundbreaking. I didn’t invent anything.

The KISS Sidewinder is a hugely popular unit. At the time of it’s development is was fairly unique unit with the split scrubber design on the sides allowing for an extremely low profile rebreather while still allowing you to carry bailout cylinders on each side. I do prefer this style of sidemount unit over one that is self-contained since it allows more space for bailouts. There are merits to both designs but I’m not going to get into them here. Mike Young’s design (and others who helped make and test it) was a huge success. It is by far the most popular sidemount rebreather on the market out there and for good and bad reasons. It is however not perfect much to dismay of the KISS fanboys out there. It should be obvious by now that no rebreather is perfect (unless you own a Meg..see what I did here?!) and they all have trade-offs.

I would say the one negative to the Sidewinder is “complete” lack of flood tolerance. A huge fucking irony here is that many people who completely shit on the rEvo for any flood tolerance are now happily diving, promoting, and selling Sidewinders and even Geminis. These are the same people that told us lack of flood tolerance is what makes the rEvo an extremely poor rebreather for cave diving. These days I would say the Sidewinder is probably one of the more popular “cave diving” rebreathers on the market.

I would also say lack of flood tolerance for both the Sidewinder and rEvo is a bit of a misnomer. Both units can sustain a decent amount of water ingress. It just so happens that this trashes the exhale scrubber. They both unfortunately lack the ability to proper de-water. I’ve experienced this a few times on the rEvo and luckily was able to stay on the unit without taking a caustic or having to bail out I realize some pedantic asshole is going to correct me here and say that is depends where the water ingress occurs. Sure, you’re absolutely right.

The point I am trying to make is while I believe flood tolerance is an importance selection criteria for a rebreather it is not a panacea. Some units are only one bad o-ring, unscrewed fitting, ripped hose or ripped mouth piece away from flooding. There are always going to be trade-offs in every design. To quote Stephen Hawking, “When something is made idiot proof, they will just make better idiots.” By that I mean it doesnt matter how simple the design is, people will always find ways to mess it up or do something wrong. I could also throw Murphy’s Law in here but that’s trite and you’ve heard it before. I don’t often get to quote Stephen Hawking in rebreather blog posts so I went with it.

What about a chestmount unit?

To be perfectly and completely truthful – I am not sold on the chestmount rebreather concept but I have not disregarded them entirely. Everyone seems to have jumped on this bandwagon. Triton, Choptima, GBM, FX-CCR, Halcyon Symbios, DiveTalk Go. I’m sure I’ve missed a few others. It’s clear people love the format otherwise there wouldn’t exist this many chestmount units on the market. I’m just not convinced it’s the best for what I want.

Full Disclosure: I hope to do some training / crossover on one in the near future just to see what I am missing since they obviously have their place and many devotees. I find it funny we spent years telling and teaching people in technical diving community to have a clean chest with no dangling bits and now we go ahead and strap an entire fucking rebreather on the front. Makes perfect sense to me..

There are quite a few cave passages where it would be largely impractical to superman the unit in front of me for the entire dive or passage. I legitimately do not think some of the caves I dive are small or tight but I can think of several caves or passages where both my belly and back were scraping through large sections. Granted I am not exactly a skinny person but adding a rebreather onto of my already large beer belly is probably not the best solution here. I know there are lots of people diving small caves with Choptimas but they’re probably skinner (and better) than me. I think they make fantastic lightweight travel rebreathers but I really dislike having stuff attached to the front of me.

So where does that leave me?

A KISS Sidewinder? I have been patiently waiting for the Sidewinder 2 to be released. It has some interesting features that look intriguing and innovative but I genuinely hate being an early adopter for things. I’ve been burned before. I feel like I’ve been a beta tester this whole time for the Dive Xtras blacktip as they changed bodies, nose cones, trigger/handle designs, speed controllers, etc. There have been so many pieces of electronics over the years that I bought as an early adopter only for the company to go out of business (Liquivision anyone?) or for them to completely drop support for that product (Subgravity Defender).

I’m sure the Sidewinder 2 is going to be a fantastic unit (once they release it) but I’d rather not be part of the first wave of units. They have been hyping the damn thing like crazy and keep pushing back the release date. I also want/need something now, not 12-24+ months from now.

My original hope was to find a used Sidewinder cheap when the Sidewinder 2 was released or somebody upgraded to a Gemini but I honestly was not finding many units below $5000usd, especially since I know I wanted certain modifications like no ADV or OPV (sump heads), dual monitors, upgraded towers.

What about the Fathom Gemini? Frankly the Fathom Gemini looks like a really beautifully engineered unit but it’s also expensive with a base price of $8,195.00. It would be awesome if one could buy it with just dual 4-pin AK cables and bring their own computers/ppO2 monitors. To be clear I have no problem with people making money. The fully potted board with SMB connectors, integrated HUD, line lock connectors on the heads are way better than latches or screw-on head connectors.

I do think that the Gemini is probably better than the Sidewinder but I’m not willing to pay that much of a markup. I’m also not convinced it’s really that much better. I also have concerns that the Fathom is for the most part a one-man show. (I do realize Charlie has other employees). The same could have been said about KISS before it got bought by XDeep’s parent company. The Gemini does look like a great unit and improves upon some of to perceived weaknesses of the current Sidewinder. In truth, every rebreather has pros/cons and trade-offs. I think I’ve said the word trade-offs four times now..

Ultimately my biggest issue is with a particular instructor that was “fast tracked” to become a Fathom instructor. A huge narcissistic, lying individual with an even bigger ego. Basically another human piece of garbage in the diving industry that thinks they’re God’s gift to diving. I know that I honestly shouldn’t let this bother me but it weighs heavily into my decision. I’d rather not buy a product if this particular individual is an instructor or “representative” of this company. Maybe one day that will change..

What about building one?

Sadly I’m not a machinist. I don’t have the talents to do any sort of CNCing however I learned a few months ago that Martin at TecMe was in the process of producing a Sidewinder clone. This intrigued me a lot. I’ve bought a decent amount of rebreather parts from him over the years. He makes good stuff. He’s like a rebreather mad scientist but in a very good way. He’s been supporting homebuilders for years and has a proven track record of building quality parts. It’s essentially Martin that is building this rebreather. I’m just adding my own electronics and assembling the lego blocks (pieces) together.

After talking to him for a bit and looking at the design I put myself on the waiting list for a set of canisters/heads. His unit is more or less a cross between a Sidewinder and Gemini.

Here is a very technical diagram I made up in PowerPoint for the Tecmewinder (sidewinder clone) when I start mocking everything up for myself. It’s very technical because I made it in MS PowerPoint instead of MS Paint.

The Tecmewinder Clone

I’m calling mine “El Serpiente” for obvious reasons. It sounds cooler than the Mayan word for snake (kaano’) although Kukulkan (plumed serpent) would also be a pretty cool name. Here are some of the features..

• Machined heads/canisters/towers out of delrin (POM)
• Towers use threaded loop connectors for standard 38/39mm hoses
• Double o-ring seal on heads to canisters
• Double o-ring seal on loop connectors to towers
• Latchless line-lock method to attach heads similar to UWLD, Genesis, Fathom
• Larger sorb capacity. Each canister holds approximately 1.5-1.6kg (total 6.5-7lbs in unit)
• Axial scrubber design with central rod of all thread and large spring and wingnut to compress sorb
• 2 x M12x1.5 ports on inhale head to allow for redundant ppO2 monitoring
• Gas Ports/Inlets use threaded metal inserts on both inhale/exhale heads
• Diluent flush option on inhale head that blows across sensors
  • I like this idea so I’m going to start with it
• Water trap design on exhale head
  • We’ll see how effective this is but both Sidewinder and Gemini dump directly into exhale scrubber and the exhale scrubber gets pretty wet. Most consider it a non-issue
• No ADV or OPV (similar KISS sump heads)
  • One could add an OPV on counterlung if desired
  • I consider both of these failure points and I don’t think the head is a great place for an OPV.

Now is the time to state that I don’t think this route is actually any cheaper than buying brand new Sidewinder or Gemini however in my case I already own a lot of parts that I can re-use for this project. I’ll do a cost analysis to give you an idea on what I spent on things vs. what I would have spent if i didn’t already own everything.

I already own the following items for this project

• AL13s for oxygen bottles (I have a few I use for suit inflation so they will be repurposed)
• Shearwater Petrel 3 (Fischer) that works on my rEvo and secondary on my Defender
• Narked at 90 HUD (Fischer) that I will use for redundant ppO2 monitoring
• Loop Hoses (Lombardi’s super stretch hoses work great)
• Extra IQSub DSV or Divesoft DSV. I can also use my IQsub Shrimp BOV here
  • I fucking love their Quick Bayonet Lock connectors!
• Apeks DS4 blocked first stage with stronger spring. I own tons of Apeks DS4s
• Subgravity/IQSub O2 MAV with built-in Swagelok needle valve.
  • I bought this for my mCCR Defender head but I can always switch back to a KISS style MAV with integrated orifice. I think Charlie’s (Fathom) design with the recessed O2 add button is way better but I already own the IQsub version and I don’t want to buy another one.
• JJ-style Diluent MAV from TecMe. I’ve been using these for years on my SF2 and Defender. They are simple, easy to rebuild and small. I really don’t like huge blocks of delrin (rEvo gas block).
• A drawer of jubilee clamps (hose clamps)
• Bungee / paracord / bolt snaps

The only things I needed to buy for this project beyond some random LP hoses and fittings were the following items.

1. Canister/Heads/Fischer Cable from TecMe ($1800USD)
2. 3x O2 sensors (uses same Molex sensors as my Defender and rEvo ($225USD)
   • Yes I hate Molex connections but at this point I like the idea of units being able to share cells and I know how to crimp molex pins. I know it’s cool to hate on molex connectors but they so common compared to coax cells. I went with easy of availability here over an arguably superior connection.
3. Sidewinder counterlung from KISS. ($389USD)
   • You’re not going to be able to build one any cheaper.
     
     Investment: $2414USD
     
     I am basically all-in for under $2500 USD. That’s not bad considering I couldn’t find a used Sidewinder under $5000 plus the modifications I would want to make to it.

Again. This route is not cheaper if you don’t already own at least some of the parts from my list above. If you had to buy everything to build this unit here is a rough estimate, not including taxes, shipping, etc. Obviously when you buy a full rebreather most of this is included in a sort of “package” so it’s not really a fair comparison.

What does this mean?

You can buy a brand new KISS Sidewinder cheaper or spend a little more and buy a Gemini. You’re not going to save any money here if you have to buy all the parts. Obviously the biggest costs beyond the heads/canisters are the electronics and probably the dual gas MAV or needle valve MAV.

Anyway last Monday my care package from Martin (TecMe) arrived courtesy of DHL from Alemania (Germany)! Sorry this is going to be VERY picture heavy.

The canisters/heads/towers are beautifully machined and tolerances are very tight on the heads and loop connectors to the towers. Admittedly I am a little worried about the metal gas inlet fittings into the delrin but it’s still way better than screwing hoses straight into the machined delrin threads. Another potential negative is the canisters themselves are a bit beefier than the Sidewinder. The Tecme canisters are 5.35″ in diameter. The plus side is almost 7lbs of sorb! I’d call it the Fatwinder but that name is already taken.

Right now I have it wired for a single fischer cable but I have plans to add a secondary cable to run my Narked at 90 HUD and use a small isolation board (Lombardi’s board is tiny). At some point in the future I’d like to swap the fischer cables out for 4-pin AK cables but that means buying all new computers. I’m not ready to make that jump quite yet.

I actually bought 4-pin AK cables already for this purpose. Well I lied, my buddy Dana gave me a couple that he cut too short but I did buy the dummy plugs and locking sleeves from Mike Lombardi.
https://www.underseatools.com/collections/electrical-components/products/wetconn-4-pin-locking-sleeve-set
https://www.underseatools.com/collections/electrical-components/products/wetconn-4-pin-female-dummy

The axial scrubber design uses a central rod of all thread with a main spring that is compressed with wing nut. It is way better than the 4 spring bullshit on the KISS canisters. There is a fixed screen at the bottom. It is very similar to the SF2, rEvo, GBM, Choptima scrubbers. I have a bunch of scrim material from my old rEvo canisters. I simply cut them down to fit inside the Tecme canisters. I’m not really sure if I actually need them but I figure it couldn’t hurt.

The exhale head has a removeable water trap. If for whatever reason you didn’t want this you could leave it out entirely.

Inhale head with sensors. The gas inlet port for diluent is setup to flush over the sensors to keep them dry and provide instant gas verification. Nothing is potted so everything is field-replaceable although I do love Fathom’s potted head design with only SMB connectors sticking out.

Assembled with IQsub/Golem DSV, Lombardi stretchy loop hoses and KISS sidewinder counterlung. These loop hoses are perfect for this unit. Although I do love the quick-lock connectors on the IQsub DSV. I am considering buying one of Lombardi’s RD1 DSVs because I want to try the 120 degree connectors he has.

The Couch Dive

Tuesday night I did the classic couch dive experiment after assembling everything on my kitchen table. As of right now the unit holds a strong positive and negative for at least an hour. I didn’t test any longer.

If you’ve ever taken a class on a mCCR unit like a KISS or rEvo (I assume Fathom too) you’re taught to calculate the O2 flow rate that you require and set it slightly below your required metabolic rate. This is easily spot checked with a Dwyer flow meter. Ideally you want to do a couch dive or a low exertion dive somewhere in a pool. I know from my rEvo days I like my unit set at around .8lpm of O2 flow. The beauty of the Swagelok needle valve is you can fine tune / tweak this on the dive if you’re scootering or working harder than expected.

The average person metabolizes about 1.0lpm of oxygen but this can change significantly with workload or rest. The O2 bottle on the rebreather is a AL13 which is considered a ~2L bottle. 2L x 200 bar provides 400L of oxygen. Not accounting for any gas loss or reserves that is about 6.5 hours of oxygen.

This is all taught (or should be taught) in any basic rebreather course. I don’t know why I am telling you this but sometimes it’s simply good to write stuff out to help myself remember.

The IP of my Apeks DS4 (with the stronger spring and blanking plug) is set to 180psi (12.4bar). I could set this higher but there is really no need. I don’t really have any plans to take this unit below 300ft (~90m) right now. I suspect most of it’s life will live in 30-50ft caves with the occasionally deeper dive though I must admit the thought of grabbing a trimix bailout and doing a nice deep wall dive in Cozumel sounds really appealing to me right now.

Harness and Regulators

After my couch dive and rebreather checks were satisfactory I spent the next 2 nights in kitchen tweaking my XDeep sidemount harness to attach everything. I’ll save that saga for another blog post but suffice to say there are a few different methods to attach to an XDeep harness. If you’re using a Katana or SMS75 it’s obviously going to be different. That is probably the single most annoying part of this entire process. I’m sure my Sidewinder and Gemini buddies are sick of answering questions, taking pictures, measuring paracord and bungee lengths for me.

I have a couple quick links attached to the top of the spine of my XDeep harness. I am running paracord from the towers, through the counterlung to the quick links with bolt snaps (I tried bungee but didn’t like it). I’m not going to get into too much detail here as I am still tweaking it and some asshole is going to tell me I am doing it wrong so I would rather not give anyone bad advice. Like anything sidemount-related there are a hundred fucking ways to do something. Jason Richard’s blog was super helpful and gave me some good ideas on mounting with the Xdeep harness.

Right now I am running my O2 MAV across my chest and that seems to work well. I haven’t figured out where I want my diluent MAV to go. I had that across the chest initially but I think I’m going to run it down my left shoulder near the chest d-ring so it matches how my other rebreathers are setup. The hose lengths are a hot mess right now and I need to tweak them but I want to do a couple more dives before I start blindly buying more random hose lengths that I don’t need. I think this where the dual gas MAV (o2/dil) would be really nice.

I’m using standard Apeks DST sidemount regulator setups for “bailout” bottles. These are setup exactly how I would use them for open circuit sidemount with the addition of another LP inflator hose on my left bottle. My left reg has my short hose on a necklace with wing inflation and right reg has my long hose hog looped around my neck and clipped off to my right d-ring with drysuit inflation. Again, that’s pretty traditional Mexico or Apeks sidemount way of doing things.

My left bottle/reg is feeding my diluent MAV via an extra LPI hose. Why no QC6 you ask? I’m glad you asked. Simplicity. I can walk into any PADI™ Five Star Jerkoff Dive Shop or SSI Total Diamond ® Bullshit Dive Center and buy an LP inflator hose. I can go to any auto parts store and buy schrader core stems. I’m also not running a BOV on this unit so I don’t need the high flow rate of QC6. Every single stage and deco regulator that my wife and I own has a low pressure inflator hose on it. It makes things incredibly simple and easy. Maybe I’ll switch it to QC6 at some point but right now I don’t need it.

My right bottle runs my drysuit and has my 7ft long hose which is pretty standard. The nice thing about this is since it’s not attached to my rebreather I can take this bottle off if I need to go through a restriction. My left bottle stays with me since it has my short hose that is bungeed around my neck and is feeding my wing and diluent.

I also deleted my SPGs and opted for Shearwater Swift transmitters last year on my primary sidemount regulators. Since the Petrel 3 has air integration I can see gas pressures right on the computer. I hate leaking SPGs. I swear to god I’ve gone through like 12 HP hoses in the past 3-4 years. I can’t tell you how many fucking times that I’ve jumped in the water only to see gas escaping from the crimp or the rubber jacket bubbling, or worse the hose just fucking bursts wide open after I hiked through the jungle in sweltering 90 degree heat and climbed into a mosquito-laden cesspool only to have to do the walk of shame back to my car to replace a hose.

I can’t tell you if the Swifts are going to be anymore reliable yet but so far they have been good. Time will tell. I still have SPGs ready in my save a dive-kit for when they inevitable fail. I also bought a bunch of stainless steel HP hoses that I have yet to test out.

First Trial Dive at Hathaway’s Pond

On Saturday unfortunately I went the only place that was really diveable last weekend, Hathaways Pond in Barnstable, MA. I absolutely hate diving there. It’s the most boring dive site in the planet. It makes Niles Beach or Back Beach look like Maldives or Galapagos by comparison.

It was actually exactly what I needed for testing this thing. Fresh water with an easy access beach entry where I can stand up in waist-deep water, predictable conditions with 20-40ft depths. It’s actually a really nice place for training and gear testing when the ocean is blown out, which it was. It was absolutely mobbed. In addition to the usual group of regular divers that always seem to be there, several dive shops were also running open water check out dives.

I spent the morning making some gear adjustments. Unfortunately my XDeep harness was adjusted for a 7mm wetsuit or a drysuit with only light undergarments which I did adjust the night before but apparently not really enough. I do not really do much cold water sidemount diving. Everything I own was adjusted for the warm waters of Mexico and Florida. I must have spent 3 trips down to the water before I even got into the rebreather, testing weighting, and fixing leaking regs. Fucking sidemount.

The gear part was actually a bit of a disaster. I immediately discovered an LP hose was leaking and cracked badly enough that I had to get out of the water to replace it. In truth, I haven’t actually touched these regs since Mexico last winter. My swivel on my bungeed secondary was bubbling, and my long hose was bubbling at the LP hose fitting. My Shearwater battery was in the red as I had neglected to change it for the past 2 dives.

To add insult to injury, I ripped a drysuit wrist seal immediately. It was ripped between my dry glove and my KUBI ring so I couldn’t salvage it. Luckily I was smart enough to bring a spare drysuit in the truck,

Just about the only thing that worked perfect was the rebreather. I was pleasantly surprised how well it dove and breathed. I mean the breathing part is really more due to the counterlung placement. It trimmed out really nice. I still need to tweak the weighting as when I reviewed the video I noticed a fair amount of gas in my wing. My only real complaint was the zip tie on the mouth piece was digging into my lip but that’s an easy fix. I may actually move some weight up higher but I don’t want to change much until I dive it a few more times

I’m not going to lie the diluent and O2 MAV hose routing was messy. In my defense I knew it was going to be. I also just wanted to get in the water after having to take everything off and switch drysuits. I just threw what I thought would work for hose lengths on there knowing full well that I would be buying new ones once I tested and tweaked a few more things. I think I am going to keep my O2 MAV across the chest and move the diluent MAV over my shoulder on left side.

Here is a quick video. I was also solo so it’s sort of hard to video yourself. Thankfully I was able to put the GoPro down on the platform to get some decent footage. Ignore the mess of leaking regulators!

After I got home I proceeded to fix all (or so I thought..) leaking hoses on my sidemount regulators and install a new wrist seal. I haven’t touched the O2 and DIL MAV hoses yet as I wanted to do one more dive before I change anything. I did not dive on Sunday as I had to work on projects around the house.

Second dive at Lake Sunapee

Since Monday was a holiday I decided to get another dive in with the unit. This time I went up to Lake Sunapee in New Hampshire. My buddy Jeff joined me and was thankfully able to film some things on the GoPro that I wanted. I don’t really care about testing things solo but it was nice having another person that could look things over and give me a really thorough bubble check.

I took off 2lbs of weight but honestly based on the amount of gas in my wing I could easily remove another 2lbs. This tracks to sort of what I would have expected. We did 90 minutes. The water was 48 degrees and I was really annoyed that I decided to wear wet gloves but my wool liners were still soaked from the other day. I hardly ever wear wet gloves.

The annoying leak I kept hearing the other day turned out to to be LP inflator hose on my O2 MAV. If I moved it a certain way it would stop leaking. I need to change that hose out for a different length anyway (it’s too short and it’s pulling on O2 bottle lopsided) so that is going to get replaced this week.

The unit felt and dived great. I had the needle valve really well dialed and it kept my ppO2 in the 1.2 range without be barely having to touch my manual O2 add button.

In conclusion, this is how to build a sidemount rebreather that is more expensive than a KISS sidewinder or Fathom Gemini and comes with no warranty. I hope you enjoyed my TED talk. I still need to get a bunch more dives in on it but I think it’s going to work out very nicely for Mexico. So far I am really enjoying but I only have a total of 165 minutes underwater with the unit.

My plan this week is to remove 2 more lbs, replace oxygen LP hose with 40″ green LP hose and adjust the dil MAV placement and then just dive it again without any other changes.

I feel it trims out really nice. The dil flush on the O2 sensors makes it really easy to do quick gas/dil verification and it seems to keep the sensors pretty dry. I also love how quickly I can do a dil flush on the unit given the small counterlung size. I miss this from my SF2 days.

The water trap on the exhale canister so far has done an excellent job of keeping all my accumulated drool, spit and lung butter (It’s technical term) out of my exhale scrubber but honestly I think it will be interesting to test on a 3-4+ hour dive. I’m sure there is a bit of loose lips at play here . I’m going to change out the mouthpiece to a DiveX Lars mouthpiece with an Aqualung lip shield. I feel these help a little bit. I have them on my IQsub Shrimp BOV.

A few things I don’t like

Getting into this thing is a pain in the ass. It’s like putting on a wet noodle and I seem to always trap a hose. I’m sure that will come easier with time and practice but I hear it’s a common complaint for newer Sidewinder / Gemini divers. If I continue to dive this thing in cold water I’m not so sure where I will put all my accoutrements like 20ah heater vest batteries, inflation bottles and canister light. I know people have already solved these problems but I am trying to start off really simple before I task load myself even further.

The loop hoses I have on it right now are really short and stretchy. They feel perfect in the water but it’s really annoying when the loop is behind your back. You have to do a lurching / jerking motion to grab the loop unless someone is there to help you. I just need to get into the habit of always keeping it around my neck to prevent this.

I definitely think I might add a small OPV on the counterlung in the future. Right now I’m absolutely petrified of walking away with my O2 turned on and it blowing up my counterlung. On a mCCR rEvo or traditional KISS unit all that happens is you end up with an empty O2 bottle the next morning.

I really detest in-line O2 shut offs and I refuse to put one on this unit but I know some people solve that problem this way. I feel they’ve killed enough people that I want them no where near my rebreathers. I guess with the vibrating ppO2 alarms of the Petrel 3 it’s less of an issue but I still don’t want one.

I’m sure I’ll find more annoying things but right now that’s all I can think of.. Until next time!