Interesting approach to automatic Buoyancy at DEMA

[TooCold]

The BCD was a wonderful idea, despite the added complication, the added failure points, and the added expense, compared to just using breathing techniques. Easy push-button control of buoyancy, and lots of buoyancy at the surface, what isn't great about that?

The idea of ditching 30 pounds (dry weight) of kit is also wonderful. But their promo video and their website don't provide very much information, and some of it doesn't add up. I hope someone from the company is following this thread (and can answer my questions):

The video says they are offering courses/diving trips in Maui. Is the tank DOT / TC / CE certified? What are the numbers? Is it certified for SCUBA?

What is the rated max depth of the kit?

What is the dry weight of the kit?

What is the buoyancy of the kit with full air (300 bar) / no water in tank?

At that air pressure, how much water can the system pump into the tank? Equivalently, what is the max change in buoyancy the system can obtain? What is the resultant air pressure? Since it's obviously > 300 bar, how is it possible to claim fill pressures to 300 bar on a tank with max working pressure of 300 bar?

 

[lowwall]

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

I watched the webinar. Here's my thoughts:

This looks like it would be a lot of fun to dive. I'll definitely give it a try someday if it's available at a not too outrageous price.

But my current rig of a steel freedom plate and 18lb wing (and no lead with an HP steel) is a lot of fun too. And that's because proper weighting and a minimalist bp/w system avoids 90% of the buoyancy issues and out of the water weight issues that this system is meant to solve. And it does it at a fraction of the cost and with much more flexibility since you won't be tied to an Avelo dive center to dive it. Speaking of a lack of flexibility...

This is a warm water only device. The max water ballast you can add at the start of the dive is about 4kg which limits you to a 5mm wetsuit unless you want to add ditchable lead. Even with a weight belt, you'd need to be very careful with your ascent with a 7mm, especially near the surface, as they mention you can only add 1 kilo negative buoyancy per minute.

Rough seas won't be fun either. At the start of the dive, you will be hanging out at the surface for a minute or three as you add enough ballast to get neutral. If you are prone to seasickness on the surface... And then at the end of the dive, you are only going to be 2-5 kilos positive, so make sure you have a snorkel or some gas left to stay on your reg if it's rough.

So what is is good for? IMO...

1) Tropical fun dives. Especially if you don't want to bring your own gear and so your rental choices are this or a typical overly buoyant and restrictive BCD.

2) Anyone who habitually dives with too much lead and has poor buoyancy control. I'm going to suggest their time and money might be better spent on buoyancy and weighting instruction than an Avelo specialty cert.

I do have have one question about this even after watching the webinar. How do you know how much gas you have left in the tank? The gas is in a bladder that changes in size whenever you let the water ballast in or out. So you start with 3000psi/200bar, but to descend you have to add ballast which shrinks the bladder so the pressure goes up to as much as 4500psi/300bar. And then as you breathe down the tank, you need to occasionally add ballast which bumps up the pressure each time. You can't really do rock bottom calculations because you never know quite how many cubic whatevers of gas you have left. I guess you just pick a number like 1200psi/80bar to start your ascent?

 

[lowwall]

The video says they are offering courses/diving trips in Maui. Is the tank DOT / TC / CE certified? What are the numbers? Is it certified for SCUBA?

Covered in the vid. They say DOT/CE certified. One of the slides has a "CE 0036" logo on it. They don't mention the DOT standard

What is the rated max depth of the kit?

200m, "designed for recreational [depths], but it can do more"

What is the dry weight of the kit?

They mention 45 pounds for the system (tank and pack). Which means their weight savings claims are assuming the non-Avelo diver is using a heavy BCD and carrying a lot of lead.

What is the buoyancy of the kit with full air (300 bar) / no water in tank?

There's a chart at 53:20 in the video that shows 2.75kg positive buoyancy for a diver at the start of the dive before adding ballast.

At that air pressure, how much water can the system pump into the tank? Equivalently, what is the max change in buoyancy the system can obtain? What is the resultant air pressure? Since it's obviously > 300 bar, how is it possible to claim fill pressures to 300 bar on a tank with max working pressure of 300 bar?

I'm estimating here. They say 200 bar without ballast is equal to 80 cubic feet of gas. So basically a 12 liter tank. 300 bar is the max pressure they mention, although they say they can do more, they don't give any numbers, so I'm sticking with 300. So if you start compressing 200 bar in 12 liters, you'll get 300 bar in 8 liters. That leaves 4 liters for ballast or 4kg (slightly more for seawater).

The same chart that shows the 2.75kg positive also shows .75kg negative after "first fill" or 3.5kg change in buoyancy. So my 4kg max is in the ballpark. BTW, it took over 3 minutes to pump in the 3.5kg of water.

 

[Jcp2]

On the one thread, there’s much bemoaning of diving being not attractive as it used to be. The gear is too heavy, too expensive, too bulky, new divers rent instead of buy, dive ops don’t care, only hard core divers stick with it, blah blah blah.
A company comes out with a lighter gear set that’s rented, not owned, simple but different to operate, with some technology that seems advanced and novel, franchised out to a dive op that is fresh and motivated to demonstrate it, and all we do is to shoot it down.
I’m willing to give it a go if I make it to Maui again. Why not? After all, I’m already using nitrox.

 

[Beau Holden]

A company comes out with a lighter gear set that’s rented, not owned, simple but different to operate, with some technology that seems advanced and novel, franchised out to a dive op that is fresh and motivated to demonstrate it, and all we do is to shoot it down.

Jcp2, you hit on a great point. Would I dive it? Maybe, no, yes. Its not about would I dive it or even that I like it or not. If it gets people into diving, then I'm for it. Who knows, down the road its figured out how they can be doubled up and make a good system.

 

[hilljo88]

Interesting.
Some thoughts:
-maintenance. How well will it handle constant salt water exposure? Parts, repair availability? 2024-2025 at earliest?
-battery. I already have about a dozen batteries to charge between camera gear, torches, etc. One more is not a big deal but battery life, weight, charging time, cost etc. are important. Can I do a 2 hour dive at BHB?
-travel. if it only weighs 40 pounds it could go into checked luggage. The developers might consider a purpose built travel case for it.
-Plan B. So given enough dives, everything fails at one time or another. The video powerpoint gives some examples of malfunctions, but I think there needs to be even more stress testing of both this system alone and in conjunction with OC dive buddies.
-Maui. Great place to live/work/vacation. But too remote to have your sole demo site if you are serious about commercialization. You need to be in California or Florida and preferably both.

I'm happy to see any attempt at innovation. For me this is somewhere past a Proof of Concept, but has a ways to go before I give it a lot of attention.

 

[Johnoly]

What is the dry weight of the kit?

I was at DEMA and stopped to talk with them also. I didn't have a scale with me but I was surprised at HOW LIGHT weight it was. If I had to guess, rigged up complete, it was half the weight of a normal AL80 + jacket BCD + weights. Like others said I dive differently, but I could see this being used at a Sandals Resort type dive center.

 

[tursiops]

Many details missing. How many cuft/liters of gas do I get?
Cost? Sorry, "comparable to other diving systems" is NOT an answer.
One spec says 4350 psi rated; am I expected to find a fill station that can do that?

 

[johndiver999]

SOME gear rental operations fail to even keep their tanks from filling up with aluminum oxide. A recent thread discussed this issue.

You are going to trust the maintenance of a complicated electrical device in saltwater after getting abused by tourists on a boat for your safety and return to the surface? Gonna wear no BC because it is too much drag for your leisurely warm water dive?

It is probably a fun toy, but not something I would use other than as a novelty.

 

[inquis]

You can't really do rock bottom calculations because you never know quite how many cubic whatevers of gas you have left.

One could use the 8 liter volume as a bounding estimate. This means dives will end early if true ballast is less than 4 kg. How likely is that? I think very.

Perhaps a HUD (4 LEDs) would be useful to show actual ballast during a dive. Unfortunately, that's getting away from the "standard" instrumentation they're shooting for.