Review Diving the Avelo System

[EdMcNeill09]

I meant, how long would a diver in an Avelo system at rest on the surface (6 lbs buoyant) take to become negative to retrieve a diver on the bottom. I am assuming the electric pump needs force water into the tank/bladder system to become neutral.

At the start of a dive an Avelo diver is 1lb positive if properly weighted. The worst possible scenario is that this is after a dive and the Avelo diver has vented water from the tank. Now the Avelo diver is potentially 5-6 lbs positive. If you have to do it this is definitely possible. Just swim down. Not easy but managable for a rescue situation. At the same time as swimming down you could be running the pump.

Funny story. Each year in Dec I put on a new 5mm wetsuit and dive it 400-500 dives until the next Dec. It keeps me warm through the winter months and warm enough into the fall. When I first trained on Avelo I ended up needing no extra weight. That was April 2022. Then I did my Avelo IDC in May of 2023 and became an Avelo Dive Center in March of 2024. This past December was the first time diving Avelo with a new wetsuit! Even worse my first dive with the new suit was while teaching Avelo. I figured I needed a couple of pounds to compensate for the new suit. I spent that first dive instructing really underweighted. I actually needed 5. My students were not aware that I was gently finning myself downwards the entire dive. I owe the CEO of Avelo an apology for telling him the weight calculation in the elearning wasn't that good. It actually is.

So basically it's not that hard to swim down 5 lbs underweighted in Avelo. It's not ideal but definitely doable in a rescue situation.

 

[EdMcNeill09]

We don’t always get to choose our emergencies. I agree about swimming down six lbs, but I am asking a pretty straightforward question. How long would it take to go from buoyant on the surface to neutral. A traditional BCD would be able to go negative in a matter of seconds.

I don’t really have an objection to the system, but I am not really seeing the upside to it either. When I look at successful innovations in diving there is usually an obvious upside. LP inflators and BCDs make maintaining buoyancy at any depth super easy. Dive computers maximize bottom time and reduce task loading. Nitrox increases the NDL on certain dives. They all add costs to diving. I don’t dive nitrox locally because the benefits relative to the price aren’t worth it shore diving to 40’.

2lbs per minute.

I only shore dive when I'm teaching Rescue but think the Avelo Weight difference would be a nice to have for shore divers. For me this is somewhere between 15-20lbs

 

[Still Kicking]

These are Carbon Fiber wrapped over thin walled aluminum. Taking the carbon fiber off the tanks would remove the strength of the cylinder. Spraying the carbon fiber wrapping with Rhinoliner protects the carbon fiber from abrasion that is looked for in the annual visual inspection. Your concern is really valid when thinking of traditional aluminum tanks that have been painted. When it comes to carbon fiber tanks the concerns during the annual visual inspection are different.

The RhinoLiner on the Carbon Fiber tank is a total winner. I dive Avelo regularly on charters and haul the tanks in my truck. They get handled exactly like my aluminum tanks and over the past year I've noticed some scuff marks on the Rhino Liner but no cuts or other penetrations.

Inspections of fiber wrapped cylinders also check for evidence of blunt-force impact damage (crazed surface of the resin, dull sound with a coin tap etc.) that might allow water to permeate the fiber weave and weaken the wrap. I don't see how this kind of inspection is possible with a Rhinoliner coating.

There was the same argument about vinyl coating protecting steel tanks. The coating only hid the damage that was going on underneath.

 

[AfterDark]

Wanted to see it on a diver…

 

[SouthernSharktoothDiver]

Question: is there an way to adjust the tank position? One of the girls in the video (3 minutes, 14 seconds in) had the tank riding pretty low, and it seems like it would get in the way. I know there's two tank sizes, and presumably she was using the larger when she should've been using the smaller one, but even so, it still looked like the top of the tank could stand to go up quite a bit. It looks like the cam bands could be adjusted somewhat, but I cannot see by how much. Anyone here know? Just curious

 

[scubadada]

Question: is there an way to adjust the tank position? One of the girls in the video (3 minutes, 14 seconds in) had the tank riding pretty low, and it seems like it would get in the way. I know there's two tank sizes, and presumably she was using the larger when she should've been using the smaller one, but even so, it still looked like the top of the tank could stand to go up quite a bit. It looks like the cam bands could be adjusted somewhat, but I cannot see by how much. Anyone here know? Just curious

The cylinder height in the Jetpack is somewhat adjustable with a strap loop that goes over the valve and neck. The system does not use a traditional cam band, it is simply a velcro closure strap. The cylinder is secured with a strap that runs from the Jetpack through a crossbar in the cage at the bottom of the cylinder.

You are correct, there are 2 cylinder sizes, 10 liter and 8 liter. The 10 L cylinder is pretty tall. I cannot locate the exact dimension but recall it is similar to a HP steel 120. Choice of cylinder size may depend on gas requirement in addition to body size. Though the cylinders are 300 bar/4350 psi, the fills I have had in Bonaire were close to those of an AL80, 207 bar, 3000 psi. At 3000 psi the 10 L cylinder would have about 71 cu ft and the 8 L would have about 57 cu ft. Of course, there is no reason you should not get a higher pressure fill and more gas volume. A fill of 3300 psi in the 10 L cylinder would give you about the same gas volume as an AL80 at 3000 psi.

 

[SouthernSharktoothDiver]

@scubadada The maximal pressure is 4000 psi, correct? What does that come out to in terms of overall ballast capacity? For example, lets say at the start of the dive I need two pounds worth of water (which from what I've seen/read, seems about like what you expect to need), what's the highest fill I can get and still add the water I need?

Also, side note, but what mechanism prevents the water pump from overfilling the tank? Like, does it switch off at 4000 psi, is there an overpressure system, or what?

 

[scubadada]

@scubadada The maximal pressure is 4000 psi, correct? What does that come out to in terms of overall ballast capacity? For example, lets say at the start of the dive I need two pounds worth of water (which from what I've seen/read, seems about like what you expect to need), what's the highest fill I can get and still add the water I need?

Also, side note, but what mechanism prevents the water pump from overfilling the tank? Like, does it switch off at 4000 psi, is there an overpressure system, or what?

No, the cylinder is rated at 300 bar, 4350 psi.

I would direct your other questions to Avelo through the form on their website, please share the answers

Avelo - Contact

diveavelo.com

 

[inquis]

what's the highest fill I can get and still add the water I need?

From upthread:

Allowing just enough room to take on 2 lbs of water for ballast, I calculate the 10L cylinder would be at 255 bar to start, including adiabatic heating and compressibility. This is about 8% more gas than an AL80 at rated pressure. (FWIW, an HP100 holds about 29% more than the AL80.)

 

[EdMcNeill09]

@scubadada The maximal pressure is 4000 psi, correct? What does that come out to in terms of overall ballast capacity? For example, lets say at the start of the dive I need two pounds worth of water (which from what I've seen/read, seems about like what you expect to need), what's the highest fill I can get and still add the water I need?

Also, side note, but what mechanism prevents the water pump from overfilling the tank? Like, does it switch off at 4000 psi, is there an overpressure system, or what?

During training you learn how much weight you need to dive Avelo with a 3000 psi 10L tank. This involves weight checks and post dive analysis. The goal is to run the pump once so that the pressure ends up around 3500-3600 psi. This is 2lbs of water and leaves you neutral if weighted properly.

So here's what you do if you want to dive a boosted tank. You fill it to 3700 or so and it cools off to 3600 or so. Now you enter the water neutral. You do not run the pump to descend. Now clearly this is not for training purposes and as a certified diver you have to understand you are not entering the water positively buoyant.

There is no shut off on psi. If you exceed 4350 psi the tank will be fine but your regs will be at risk of free flowing as your regs are designed with a 300 bar maximum pressure. This is why in training we emphasize looking at your gauge when running the pump. First to ensure pressure is rising and second to ensure you do not exceed 300 bar.