Review Diving the Avelo System

[SouthernSharktoothDiver]

@scubadada I'm given to understand the existence of non-ditchable weight is something of a touchy subject in some scuba circles, but one can hardly fault Avelo for having it, given that other scuba systems do as well. IMO, anyone who just dives in with not just an excess of weight, but more weight than they can reasonable kick up to support themself with, is likely outside the realm of what I would call the system's fault, but I do think, if Avelo takes off, that will happen eventually, so brace yourself lol.

Side note, but this does make me think: How much does a typical person's weight requirement change, season to season, you reckon? As I've mentioned elsewhere, I don't generally dive neutrally buoyant because I'm river diving, and I haven't been diving that long anyway, but I could definitely see it being something of an inconvenience for your average, once-a-year vacation diver, if every time they rent Avelo they've got to hop in a pool or something and re-discover their appropriate lead for neutral buoyancy. Safer, perhaps, than just tossing 20 pounds on and half filling a BCD, but definitely an annoyance, since Avelo requires such close tolerances. I suspect most people probably dive at least 1-2 pounds over (so like, 7 lbs at the start of the dive, 2 at the end when air is depleted) and then use a little air to compensate. How much margin does Avelo give you for that sort of adjustment? It's only capable of a few pounds difference, right?

As I said, definitely better diving, with BCD or Avelo, to have your exact weight profile figured out, but I can't imagine the vacationer crowd being too pleased to fiddle with it every year.

 

[inquis]

How much does a typical person's weight requirement change, season to season, you reckon?

Surprisingly little. If people lose weight overall, usually most of it is fat (which is less dense than the surrounding water at 0.9 g/cm3) but they typically gain some muscle as well (more dense than the water at 1.06 g/cm3). For example, if someone loses 12 lbs overall, that might have been from <losing 12 lbs fat> or <lose 13 lbs fat, gain 1 lb muscle> or <lose 14 lbs fat, gain 2 lb muscle>, ... <lose 22 lbs fat, gain 10 lb muscle>. The net impact on overall buoyancy by losing a total of 12 lbs ranges from -1.3 lb to -3 lbs for the previously outlined range of individual tissue losses. As you'd expect, the reverse holds (increase buoyancy by 3 lbs by gaining 22 lbs fat and losing 10 lb muscle, again a 12 lb total gain) -- holiday pie anyone?

 

[CT-Rich]

Surprisingly little. If people lose weight overall, usually most of it is fat (which is less dense than the surrounding water at 0.9 g/cm3) but they typically gain some muscle as well (more dense than the water at 1.06 g/cm3). For example, if someone loses 12 lbs overall, that might have been from <losing 12 lbs fat> or <lose 13 lbs fat, gain 1 lb muscle> or <lose 14 lbs fat, gain 2 lb muscle>, ... <lose 22 lbs fat, gain 10 lb muscle>. The net impact on overall buoyancy by losing a total of 12 lbs ranges from -1.3 lb to -3 lbs for the previously outlined range of individual tissue losses. As you'd expect, the reverse holds (increase buoyancy by 3 lbs by gaining 22 lbs fat and losing 10 lb muscle, again a 12 lb total gain) -- holiday pie anyone?

My guess is your overall density really doesn't change much based on gaining losing weight. the configuration of your gear will have the biggest impact. Going from a dive skin to a 3 mm wetsuit or using a steel tank versus an aluminum tank, a BP/W versus a BCD will certainly have more effect on most divers than diet and exercise.

 

[SouthernSharktoothDiver]

@inquis @CT-Rich Interesting. So perhaps getting properly weighted in once and then getting advice from the rental place/dive crew on how to adjust for different wetsuits, etc, would be sufficient. One less hassle to worry about then, and a point towards the viability of the product, especially since most of the variation is removed by having a standard tank, backplate, batteries, and all that. I do wonder if they have a variation in weight recommendation for the 10L vs the 8L hydrotank, or if it's balanced well enough to not need it. It'd be easy enough to say "The 10L needs an extra pound," but on the other hand, a rather neat trick if they managed to design it with a capacity to material ratio such that both have the same buoyancy profile. Not much of a difference, either way, but it'd certainly be a cool detail if it was that fine tuned.

 

[CT-Rich]

@inquis @CT-Rich Interesting. So perhaps getting properly weighted in once and then getting advice from the rental place/dive crew on how to adjust for different wetsuits, etc, would be sufficient. One less hassle to worry about then, and a point towards the viability of the product, especially since most of the variation is removed by having a standard tank, backplate, batteries, and all that. I do wonder if they have a variation in weight recommendation for the 10L vs the 8L hydrotank, or if it's balanced well enough to not need it. It'd be easy enough to say "The 10L needs an extra pound," but on the other hand, a rather neat trick if they managed to design it with a capacity to material ratio such that both have the same buoyancy profile. Not much of a difference, either way, but it'd certainly be a cool detail if it was that fine tuned.

these hydro tanks are likely to come in one size. they are more complicated than a traditional tank, and they are not manufactured on the scale needed to justify more than one tank.

 

[SouthernSharktoothDiver]

@CT-Rich according to the flyer thing I saw for the system, there were two sizes available, 8L and 10L. It is possible this has changed without me knowing, but I thought there were those two.

 

[scubadada]

Yes, there are 2 tank sizes, 10L and 8L. You input the tank size in the Avelo Mode so that it can calculate RMV. I have only dived the 10L tank.

 

[CT-Rich]

@CT-Rich according to the flyer thing I saw for the system, there were two sizes available, 8L and 10L. It is possible this has changed without me knowing, but I thought there were those two.

You may be right, I haven't really been following the development of a product I see no reason to buy. I wonder how modular the system is. How much are just the tanks? I usually do three plus tanks on vacation.
According to the AI summary, each additional tank costs between $900 and $1,100.

A new Aluminum 80 (10L) is less than $200 (by a lot). A This is pretty much competitive with the a Go, or most other bare bones CCR with none of the utility. If I was going to go on a Tropical vacation and was already scuba certified, what does the Avelo provide me that I wouldn't get from regular OC? If I don't understand controlling buoyancy, is this machine going to fix that? Or am I going to use the the button like an elevator? I need to have a Shearwater computer (plus a $100 app) to use it, a training course ($$$$) on top of the cost of standard open water certification.

It is probably safe, but it is unproven (there are not the millions of hours of use associated with traditional OC), so I wouldn't even consider telling a novice that it is Scuba with training wheels. Despite appearing safe, look at the recent history of of the full face snorkel masks. Seems like a pretty no brainer product for novices, but there have been enough casualties that boats won't let you use them.

 

[SouthernSharktoothDiver]

what does the Avelo provide me that I wouldn't get from regular OC?

Best I can tell, they're marketing it three ways.

First and most minor of which is that it's more streamlined, and improves your SAC correspondingly. IIRC, @scubadada reported some improvement in SAC while using it, but I'm not sure how much. I'm also not sure what the standard fill is for Avelo. They say the hydrotank can hold up to 300 Bar, but then in practice you can't fill it that high cause you need to leave "room" for the water ballast. So is that, 250 Bar? 200? I don't think you're get much more air in the biggest tank than an AL 80, and at most optimistic, no more than an HP 100, so if maximizing bottom time is such a major concern, you don't have the option of packing in a larger tank. That being said, most vacation sites only seem to have 80's anyway best I can tell, so in practice I don't know how much difference that makes.

The second claim is that it's lighter. Best I can tell, this is true (though likely not as dramatic as they claim). They say on their site the average diver's rig weighs 75 pounds which is...widely overestimating. I dove at a charter on Oahu earlier this year, using a standard vacationer setup (scubapro, jacket BCD, shortie wetsuit), needed 10 lbs of lead and the whole rig weighed, with AL 80, probably 50-55 pounds. Assuming avelo weighs the 45 lbs they estimate it weighs on their website, that's a saving on 5-10 lbs compared to a vacationer's rig. Less of a saving compared to a Bp/w setup, but for warm water, single tank, destination diving, the majority of people seem to dive jacket style. So, this claim does seem true (though nowhere near the 30 lbs they estimate on their site), but there's something of a footnote to be considered.

I don't have a spec sheet with the weight of each individual part, so I'm guessing here, but I suspect most of Avelo's weight savings comes from the carbon fiber tank and the lack of (highly buoyant and IMO unnecessary) padding that most jacket BCD's have. Thus, if dry weight is your biggest concern, I think you could be as light or lighter than avelo with a minimalist backplate and wing and a carbon fiber tank, though I can't say for sure. I suppose there is also some loss of weight on the surface since you're adding ballast once in the water, but from what I can tell from reviews, you add a few pounds of ballast at most, so the peak savings from that factor would be perhaps 5 pounds. So, the verdict, best I can tell, is that it's lighter than a jacket style by perhaps 5-15lbs, but could likely be matched by a custom OC setup if weight is your sole and singular concern. Then again, if surface weight is your biggest concern there's side mount, but let's not get into all that here.

The last claim is the buoyancy is constant, except for loss due to air which is easily managed using the ballast pump. This claim seems true both from the design principles and the user reviews. You can change depth without changing buoyancy. My thing is, remember my days as a new diver, excluding the very earliest dives (like, my open water checkoffs and the dive immediately after it), buoyancy change while deliberately changing depth was never than big of a deal. If I'm planning to change depth, I just adjust my buoyancy to suit. It was holding a good, steady buoyancy and trim while at a constant depth, (ie getting it "dialed in" and accounting for my breaths) that took a while longer to manage, and I suspect having a class on the subject (such as Avelo's certification course) would've made it a done deal regardless of the gear I'm using.

So, my conclusion is that the product does what it claims, but that I'm not sure if the juice is worth the squeeze. After all, even ignoring costs, this system, even as advertised, just does one thing really, really well. I definitely think it's more suited to the rental market than the private consumer (unless you do a lot of single tank, open circuit, neutral diving near where you live, and don't have any special activities that might require modifications). I do think the novelty and simplicity might be enough to attract vacationers to it (heck, if it was cheaper or if I had more money, I might give it a go simply to see what all the fuss is about. As is that $450 course fee, $250 guided dive fee, and $110/day rental's a bit of a barrier). It does seem to be spreading/gaining locations, so assuming they can keep the momentum going, it looks like it's here to stay. Time will deal.

This system doesn't appeal to me, much, because it's not the kind of diving I do very often, but I can see how it might be a step up in comfort for those who do. I'm most interest in seeing what they do next. If Avelo's current product succeeds, they'll inevitable make something new, and that might be something I'd actually use. It'd require some serious work, but I can see how this system could be applied different to other, more versatile forms of diving.

 

[scubadada]

...First and most minor of which is that it's more streamlined, and improves your SAC correspondingly. IIRC, @scubadada reported some improvement in SAC while using it, but I'm not sure how much...

Actually, what I reported was that my gas consumption was somewhat higher than with traditional gear when I was certified and dived Avelo gear in December 2023. In October 2024, my gas consumption on Avelo decreased to be equal to my gas consumption with traditional gear. My buoyancy and gas consumption was already quite good. My average RMV on the recent Bonaire trip was 0.31-0.32 cu ft/min with traditional and Avelo gear over 36 dives, 6 on Avelo.