Interesting approach to automatic Buoyancy at DEMA

[tridacna]

Nor gas weight changes

Precisely. The idea is an old one. Replacing a floppy wing with a rigid one impervious to pressure changes. It’s their implementation that is unusual. I saw a similar device: A.B.C.D. at DEMA about 5 years ago. It went nowhere.

 

[lowwall]

Dare I suggest new readers of this thread go back at least to my 2 posts starting at Interesting approach to automatic Buoyancy at DEMA

A big takeaway for me is that this looks limited to warm water and benign conditions. It looks like you have a maximum of around 4kg/9lbs of bouyancy available at the start of the dive to compensate for wetsuit compression. Even though you don't need additional bouyancy to compensate for changes in the weight of the gas in the tank, this is still equivalent to a conventional setup with a 14 or 15 pound wing.

To me this makes it suitable for use with no more than a 3mm suit. And even that assumes you will not want any reserve lift to help out a buddy who has some kind of problem.

This also suggests the most honest comparison for this is a setup like my steel Freedom plate with 18lb wing along with an HP100. Do this comparison and what's left are pretty small differences in topside weight and underwater drag for the large difference in cost and ability to easily do multiple dives.

 

[scubadada]

Nor gas weight changes

You do lose the weight of gas consumed, as expected. An adjustment is made partway through the dive to correct this and maintain neutral buoyancy

You might want to take a look at the Avelo website and take a look at the videos linked in this thread to help answer your basic questions

Avelo - Technology

diveavelo.com

 

[L13]

After you adjust, you continue to consume air. If you adjust to neutral, you weren't neutral before the adjustment, and you won't stay neutral after. There must be a strategy to mange being slightly out of neutral through out the dive.

Since the deviation from neutral due to air consumption can be kept under 0.5 kg (1 lb) with 1 adjustment, breath control can easily be used to compensate. A flash back to pre-BCD diving, but with a much smaller magnitude to be breath controlled.

 

[KenE]

The way I see it is that you start out as neutrally buoyant. It the battery fails, you can swim up at a leisurely rate, probably hold your safety stop and then vent the water and make your final ascent. This is nothing like an uncontrolled ascent. Take a look at the information that is available in the public domain, you would understand this.

With all due respect, a 7mm wetsuit on a 250lb guy at 120 ft will gain alot of bouyancy as you try to swim ascend to the surface. You will be in an uncontrolled ascent before you reach safety stop and you will not make any stops on the way to the surface.

 

[azstinger11]

Hmmm looks like a local dive shop has a small fleet of these, need to reach out and see about getting a dive in! There are a couple of permanent buoys I can test the buoyancy swing at too. Also interesting location for the first cold water site of these, probably one of the best shore dives in Southern California.

 

[yle]

Near the start of the video the guy says the system is pumping salt water into the cylinder.

Sure, that sounds like a good idea... salt water inside a cylinder isn't much of an issue. Definitely a "solution" in search of a problem. Which is probably why they promote it as "the future of diving", because they assume sometime in the future they'll find that problem they're searching for.

 

[3DzeroG]

So instead of a single-tank recreational wing (3 lbs weight), I would have to put this 40 lbs contraption into my check-in baggage? And I'd have to take out the valve to get it on the plane, too? And if I want to do two dives, I need to have it filled during the surface interval instead of just putting my kit on a fresh cylinder? And the annual cylinder service involves… what exactly?

Sure, sign me up. :/

 

[eelnoraa]

Before you go too far off without details, maybe watch this:

This is Dan Orr, the former CEO of Divers Alert Network and chairman of the WRSTC. During 2022, the largest brands in scuba sent their top level people to participate in the pilot. The result was multiple collaborations with all of them. The one that was revealed at DEMA was the one with scubaPRO. There is so much more depth to this approach and technology that is not obvious until you dive it. The webinar helps more than anything else. In a nutshell - diving this system is like switching from a sedan to a high-speed motorcycle. It is a far better overall experience, but you need to know what you are doing.

And by the way - there is nothing automatic about it. The system is manual.

I watched the entire video Dan for sure get paid on this. He cannot stop saying how good this setup is. And we know in life, espcially in scuba, nothing is that one sided.

The first thing I don't get is the size of the tank. Typical AL80 is a 11L tank. 18lb wing (consider smaller for tropical diving) is about 8L in volume. If this tank is the same size of AL80, and allocated 18lb worth of air space for lift, then the left over la 5L for breathing gas. At 3000psi, this is about 50CF of breathing gas in it, give or take. It will be a short dive. They said they often dive this to 150ft for, with a 50CF of air??

Must of the problem discussed in this video is a weighting problem. Tropical diver carry too much weight, so when BC fail, they sink like rock. Or they carry too big of wing, when inflator get stuck they ascent uncontrollably. With this Avelo, it is kind of force the diver to be weighted correctly, otherwise, diver won't even be able to float head out of water. But then if the diver is weighted properly, then BC failure isn't an problem either.

 

[KenE]

I watched the entire video Dan for sure get paid on this. He cannot stop saying how good this setup is. And we know in life, espcially in scuba, nothing is that one sided.

The first thing I don't get is the size of the tank. Typical AL80 is a 11L tank. 18lb wing (consider smaller for tropical diving) is about 8L in volume. If this tank is the same size of AL80, and allocated 18lb worth of air space for lift, then the left over la 5L for breathing gas. At 3000psi, this is about 50CF of breathing gas in it, give or take. It will be a short dive. They said they often dive this to 150ft for, with a 50CF of air??

Must of the problem discussed in this video is a weighting problem. Tropical diver carry too much weight, so when BC fail, they sink like rock. Or they carry too big of wing, when inflator get stuck they ascent uncontrollably. With this Avelo, it is kind of force the diver to be weighted correctly, otherwise, diver won't even be able to float head out of water. But then if the diver is weighted properly, then BC failure isn't an problem either.

I believe you are omitting the change in bouyancy is not limited to the cylinder. Bouyancy changes with depth in cold water due to exposure suit bouyancy. Wetsuit is not controllable like a drysuit. A XXXL 7mm wetsuit at the surface if very bouyant and not at 100 fsw. A failure of the pump could mean an uncontrolled ascent, a big problem if a stop is desired or required.