Review Diving the Avelo System

[SouthernSharktoothDiver]

@scubadada Could we see the breakdown of how it's saving you the weight? My standard rig when I'm diving for fun (and not for fossils, when I would go in very negative to allow me to remain on the bottom where the teeth are) is an ~8lbs bp/w, ~35 lb tank+gas, call the reg and dive computer two pounds, and I'll usually toss eight pounds of lead onto that just to be on the safe side. I suspect I could get away with as little as 4, but I don't often dive neutral and prefer not to risk fighting positive buoyancy when making my safety stop. One of these days (next summer, probably) I'll sit down and get my weighting dialed in, but that's beside the point for now.

My whole dive rig weighs maybe 50 lbs, and I feel like this is about typical for relatively warm water without any special equipment (ie, pony bottles, stages, etc). Where does Avelo offer such weight savings? The only thing I can figure is that the fancy carbon fiber tank is much lighter, but if that's the case, you can dive standard with a carbon fiber tank.

I'm not saying you're wrong, mind you, I'm just wondering where the savings are at. It feels like Avelo should weight about the same, since you still have the same base components (tank, reg, plate, lead), with the added weight of a pump and a battery. Is it the tank that's lighter, or something else?

 

[scubadada]

Hi @SouthernSharktoothDiver

You are not the first to ask for a detailed weight accounting. I have not meant to be evasive. Unfortunately, the weights of the Hydrotank and the Jetpack are not in the public domain and I do not feel free to post them. The weights can be found in the Recreational Avelo Diver e-Learning course. I have suggested to Avelo to include this information on their website so that divers can make their own comparisons.

The only variables in a weight comparison for me are the 10L Hydrotank vs AL80 (34 lbs), Jetpack vs my BC (Scubapro Knighthawk 8.8 lbs), and weight used with Avelo (4 lbs) vs weight used with standard gear (10 lbs). Regulators, fins and mask, wetsuit, and gas in the tank are the same for both. For my dives in Bonaire my Avelo cylinders were filled to about the same pressure as my AL80s, so I actually had a little less gas. If one used a tank other than an AL80, you could simply use that tank and valve weight and account for any difference in gas weight.

So, for me, the weight of the Avelo gear was just under 15 lbs lighter than my traditional gear. The main weight savings are in the Hydrotank and the amount of weight used. The Jetpack weighs more than my BC.

While in Bonaire, I heard that a new version of the Hydrotank will be released and will weigh somewhat less.

 

[SouthernSharktoothDiver]

Unfortunately, the weights of the Hydrotank and the Jetpack are not in the public domain and I do not feel free to post them.

I mean, you do you I guess, but it’s a thing anybody with a scale could figure out, and honestly a pretty crucial piece of info for a prospective buyer. If Avelo’s not releasing that info, I’m left to conclude that either they weigh too much and Avelo’s hiding it, or that they’re too stupid to release how important that info is for marketing. You can quote me on that to whoever makes that decision at the company if you like.

I also don’t really get why Avelo would require less weight compared to a minimalist/hogarthian Bp/w since it’s hard to get much denser than a steel plate, empty wing, and nylon straps. As for tanks, presumably a carbon fiber tank with a higher density of air will, by the end, be less dense. Sure, the added water ballast maybe offsets some of your need for lead, but I just don’t see how it adds up to much less if any, since as you’ve said, you seem to only use~4lbs of water for ballast

 

[CT-Rich]

I am not clear why Carbon fiber tanks would be of interest. You need to displace the density of the tank and air. The big advantage of steel over Aluminum is that steel offsets the extra lead required to make tank sink. Also, you may want to check with SeaGate about the limited life span of Carbon fiber pressure vessels.... they have some experience with them..

In salt water, you need to make the diver and his gear have a density equivalent to the surrounding water. I have not tested it, but I assume my SP NightHawk has a positive buoyancy if I tossed it tankless in the ocean, plus any residual air.

With just a rash guard, I need about 18 lbs with an AL100 and the BCD. I seldom have to much beyond a spritz of air to maintain trim at depth. I am not sure how a carbon fiber tank would improve this significantly, especially at the cost of $3,700. At the end of the dive that tank is going to be very floaty and the change in buoyancy going from 4500 psi to 500 is not going to change either. Physics is a cruel mistress....

Just looked at the Homepage. Does this System involve changing the volume in the high pressure vessel? I assumed it used two trim tanks. Now I really have to say, I don't see how this system works....

Avelo - The Avelo System

diveavelo.com

 

[Still Kicking]

Also, you may want to check with SeaGate about the limited life span of Carbon fiber pressure vessels.... they have some experience with them..

This is a bit of a red herring.... Ocean Gate was wrapping it's own hull using fiber that was apparently of questionable quality and an unproven design.

According to PSI, the tanks Avelo is using are top grade. (However, coating them in protective Rhinoliner-like vinyl, as some dive centers say they are doing, may present a problem).

Not to mention the tens of thousands of fiber wrapped tanks in service with fire departments, fumigators etc. for SCBA.

There are questions about the viability of Avelo but the quality of the tanks is apparently not one of them.

 

[scubadada]

...Just looked at the Homepage. Does this System involve changing the volume in the high pressure vessel? I assumed it used two trim tanks. Now I really have to say, I don't see how this system works....

Avelo - The Avelo System

diveavelo.com

Yes, the volume and pressure of the high pressure vessel is changed.

Scroll down to the figure "How does the Hydrotank work?" Click on the On/off button and then on the Purge valve.

 

[lowwall]

I am not clear why Carbon fiber tanks would be of interest. You need to displace the density of the tank and air. The big advantage of steel over Aluminum is that steel offsets the extra lead required to make tank sink. Also, you may want to check with SeaGate about the limited life span of Carbon fiber pressure vessels.... they have some experience with them..

In salt water, you need to make the diver and his gear have a density equivalent to the surrounding water. I have not tested it, but I assume my SP NightHawk has a positive buoyancy if I tossed it tankless in the ocean, plus any residual air.

With just a rash guard, I need about 18 lbs with an AL100 and the BCD. I seldom have to much beyond a spritz of air to maintain trim at depth. I am not sure how a carbon fiber tank would improve this significantly, especially at the cost of $3,700. At the end of the dive that tank is going to be very floaty and the change in buoyancy going from 4500 psi to 500 is not going to change either. Physics is a cruel mistress....

Just looked at the Homepage. Does this System involve changing the volume in the high pressure vessel? I assumed it used two trim tanks. Now I really have to say, I don't see how this system works....

Avelo - The Avelo System

diveavelo.com

You should read through this thread. All this has been covered. Quoting myself from post #73

"The outer cylinder is a carbon wrapped AL shell. The gas is held in a bladder inside the cylinder. It is attached at the valve at the top of the cylinder. Adding ballast is done by pumping water into the cylinder (but outside the bladder) which compresses the bladder. The bladder is filled to an initial pressure below the cylinder's rated capacity so you can safely add up to 4 liters of ballast water at the beginning of the dive.

Dumping ballast does not require the pump. You manually open a purge valve which allows the gas pressure to expand the bladder and thus expel the (ambient pressure) ballast water.

Avelo has a little animation of this here: Avelo - Technology [the link no longer works]

I took a screenshot of it during the animation of the purge (blue is the ballast water).

"

 

[scubadada]

Hi @SouthernSharktoothDiver

You are not the first to ask for a detailed weight accounting. I have not meant to be evasive. Unfortunately, the weights of the Hydrotank and the Jetpack are not in the public domain and I do not feel free to post them. The weights can be found in the Recreational Avelo Diver e-Learning course. I have suggested to Avelo to include this information on their website so that divers can make their own comparisons.

The only variables in a weight comparison for me are the 10L Hydrotank vs AL80 (34 lbs), Jetpack vs my BC (Scubapro Knighthawk 8.8 lbs), and weight used with Avelo (4 lbs) vs weight used with standard gear (10 lbs). Regulators, fins and mask, wetsuit, and gas in the tank are the same for both. For my dives in Bonaire my Avelo cylinders were filled to about the same pressure as my AL80s, so I actually had a little less gas. If one used a tank other than an AL80, you could simply use that tank and valve weight and account for any difference in gas weight.

So, for me, the weight of the Avelo gear was just under 15 lbs lighter than my traditional gear. The main weight savings are in the Hydrotank and the amount of weight used. The Jetpack weighs more than my BC.

While in Bonaire, I heard that a new version of the Hydrotank will be released and will weigh somewhat less.

I mean, you do you I guess, but it’s a thing anybody with a scale could figure out, and honestly a pretty crucial piece of info for a prospective buyer. If Avelo’s not releasing that info, I’m left to conclude that either they weigh too much and Avelo’s hiding it, or that they’re too stupid to release how important that info is for marketing. You can quote me on that to whoever makes that decision at the company if you like.

I also don’t really get why Avelo would require less weight compared to a minimalist/hogarthian Bp/w since it’s hard to get much denser than a steel plate, empty wing, and nylon straps. As for tanks, presumably a carbon fiber tank with a higher density of air will, by the end, be less dense. Sure, the added water ballast maybe offsets some of your need for lead, but I just don’t see how it adds up to much less if any, since as you’ve said, you seem to only use~4lbs of water for ballast

There is sufficient information in my post for anyone to do their own calculation.

 

[lowwall]

Ok, I've seen Avelo's weight and displacement chart. I don't want to give away the actual numbers in respect to the person who shared it with me, but I will share this.

On the most detailed comparison I could come up with using my own gear and an HP80, the Avelo system ends up only 2kg (4.5 pounds) lighter.

My gear is a large steel Freedom Plate without wedge, standard continuous harness and VGDH 18# wing.

Why an HP80? It matches the rated capacity of Avelo and my feeling is that it above water weight is a very important factor for your, you would be willing to spend a little money and effort to source an HP80 versus a lot of money and effort to use Avelo. If you want to use an HP100 instead, the weight difference goes up to 6.5kg (14 pounds), but of course you get 25% more gas and, for most of us, better trim characteristics.

What is clear from my calculations is that Avelo's weight examples work only if they are assuming an overweighted diver with fluffy jacket BCD and an AL80. For those that really care about system weight, you can easily get within 5 pounds of Avelo with conventional gear.

[Edited to correct the weight savings for Avelo. I had originally added 3 pounds of lead to the Avelo system to allow enough negative bouyancy to get under, but I had forgotten to include the weight of the gas when starting a dive. When this is included the need for additional ballast with Avelo should go away for most people with up to a 3mm suit.]

 

[MarkA]

Ok, I've seen Avelo's weight and displacement chart. I don't want to give away the actual numbers in respect to the person who shared it with me, but I will share this.

On the most detailed comparison I could come up with using my own gear and an HP80, the Avelo system ends up only 700 grams (1.5 pounds) lighter.

My gear is a large steel Freedom Plate without wedge, standard continuous harness and VGDH 18# wing. The Avelo system gets a small amount of lead for the initial descent that is consistent with what @scubadada and his wife needed as mentioned in the original post on this thread.

Why an HP80? It matches the rated capacity of Avelo and my feeling is that it above water weight is a very important factor for your, you would be willing to spend a little money and effort to source an HP80 versus a lot of money and effort to use Avelo. If you want to use an HP100 instead, the weight difference goes up to 5kg (11 pounds), but of course you get 25% more gas and, for most of us, better trim characteristics.

What is clear from my calculations is that Avelo's weight examples work only if they are assuming an overweighted diver with fluffy jacket BCD and an AL80. For those that really care about system weight, you can easily get within a pound or two of Avelo with conventional gear.

And with an 8l 300bar cylinder with the light weight wing, you just may get it the odd pound lighter.

Diving cylinder 8 litres complete 300 bar diameter 140mm with valve an

Diving tank 8l complete300 Bar, long version 140mm diameter ideal for women Steel tank stamped Breathing Apparatus

www.tek-diver-shop.de

But on holiday in North America you are probably stuck with an AL80, so the 15 lbs is probably about right for most people.