Review Diving the Avelo System

[hammet]

What I don't understand is why the need to solve the "problem" of neutral buoyancy. It seems like the selling point of the avelo system is to move up and down the water column with no need to add or remove air to a bcd thus making it a thoughtless process. However, ascending and descending must necessarily be a mindful procedure. The lack of need to consider the air inside ones non existent bcd does not remove the need to be cognizant of the air within the diver's body. Thus, ascents must continue to be slow, NDLs and MODs must be respected, the threat of narcosis identified, and equalization of ears must still be carried out as required.

 

[Wibble]

What I don't understand is why the need to solve the "problem" of neutral buoyancy. It seems like the selling point of the avelo system is to move up and down the water column with no need to add or remove air to a bcd thus making it a thoughtless process. However, ascending and descending must necessarily be a mindful procedure. The lack of need to consider the air inside ones non existent bcd does not remove the need to be cognizant of the air within the diver's body. Thus, ascents must continue to be slow, NDLs and MODs must be respected, the threat of narcosis identified, and equalization of ears must still be carried out as required.

E.g. wetsuit expansion near the surface or putting up a SMB

Someone used to managing changing buoyancy requirements wouldn't even notice that. It becomes an issue if it's new to someone diving with constant buoyancy.

 

[inquis]

Someone used to managing changing buoyancy requirements wouldn't even notice that.

The flip side is also true. As you know, a CCR diver typically has 3 airspaces to manage (not counting your lungs). After my certification (i.e., still at the conscious competency stage on CCR), it was SOO nice/easy doing an OC dive with "only" 2 airspaces (wing/drysuit). I can totally understand new/infrequent rec. divers -- someone at the conscious-competency stage of managing just the wing -- REALLY liking Avelo's reduced frequency of adjustment.

 

[EdMcNeill09]

We all use ballast, mostly in the form of lead and occasionally in the form of a stainless steel plate shaped to allow the addition of a tank, wing and harness. Since the invention of the BCD, divers have added sufficient ballast to get themselves neutral at the most buoyant part of the dive, i.e. when they are shallow (if wearing neoprene) and have used up most of their gas. This means we are overweighted for the rest of the dive which we compensate for by increasing our volume without increasing our weight (by adding gas to a wing), thus decreasing our system density. The problem this creates is that the gas bubble and thus system volume will fluctuate with changes in depth, especially when shallow, which requires the diver to react by changing lung volume or adjusting the amount of gas in the wing.

Yes. I was inaccurate when I said Avelo was the first successful attempt to use ballast! I should have said "to use water as ballast".

Avelo, on the other hand, increases density by adding ballast in the form of water while keeping volume the same. The advantage of Avelo is that since your volume doesn't change, your overal density will only change very slowly as you use up gas. So once you are close to neutral, you will stay there for many minutes even as you ascend or descend (assuming you are not using a heavy wetsuit). The disadvantages all come from using water as your ballast material. The main disadvantage is the low density of water (approx 1.03 g/cc for sewater) compared to lead (11.2 g/cc) or stainless steel (8 g/cc) means it takes a lot of space, thus limiting how much you can add. This in turn means you need a physically large cylinder for the amount of gas it carries, you have limited positive buoyancy on the surface and limited ability to counteract the volume changes of thick neoprene as you descend and ascend. These factors make Avelo unsuited for rough or cold water. Another disadvantage is that adding water to the same volume that already contains high pressure air means you need the added complexity, cost and potential failure points of a high pressure pump, electronics, and a battery. You also have to keep the battery charged and pay attention to its charge state.

Avelo works very well in cold water. Well I guess it depends on what we mean by cold. I don't know that anyone has taken it ice diving yet, but it's available in California at Catalina Divers Supply and I heard a rumor that it will be in Monterey soon. So 50-60 degree water is not a problem. Neoprene is less of an issue than most people think. Drysuits are also not a problem. There's a Dry Suit diver in Catalina diving Avelo with no extra lead. Now that blows my mind.

Rough water isn't really an issue either. I dive in the Pacific Ocean and regularly have to deal with significant chop and swells. Lake like conditions are the exception in Hawaii.

I just can't see this taking off except for possibly a small subset of wealthy tourist divers who will happily pay a premium to have someone else handle the details of their Avelo dives. But I suspect the need to get weighting just right is going to be a problem for these folks.

I'm teaching Avelo to tourists and it's pretty simple. We usually get the weight sorted by the second dive. And yes, tourist divers love it. Actually almost everyone who dives it loves it.

 

[EdMcNeill09]

The flip side is also true. As you know, a CCR diver typically has 3 airspaces to manage (not counting your lungs). After my certification (i.e., still at the conscious competency stage on CCR), it was SOO nice/easy doing an OC dive with "only" 2 airspaces (wing/drysuit). I can totally understand new/infrequent rec. divers -- someone at the conscious-competency stage of managing just the wing -- REALLY liking Avelo's reduced frequency of adjustment.

None of us became divers to become good a buoyancy control. We became good a buoyancy control to become good divers. Avelo makes it easier for people to become confident and competent divers.

As an Instructor approaching his 65th birthday I appreciate the substantial weight difference. My Avelo set up weights just a little more than a full aluminum 80. I really need to weigh it. I almost never shore dive anymore as I'm on boats 5-6 days a week. But shore diving with Avelo would be fun. Older or aging divers, or divers with physical limitations, will appreciate Avelo.

 

[lowwall]

None of us became divers to become good a buoyancy control. We became good a buoyancy control to become good divers. Avelo makes it easier for people to become confident and competent divers.

As an Instructor approaching his 65th birthday I appreciate the substantial weight difference. My Avelo set up weights just a little more than a full aluminum 80. I really need to weigh it. I almost never shore dive anymore as I'm on boats 5-6 days a week. But shore diving with Avelo would be fun. Older or aging divers, or divers with physical limitations, will appreciate Avelo.

Have you ever dived or taught anyone using a steel BP with compact wing and an HP100 or HP80? The weight is very close to the full Avelo system as most people need little if any additional lead. It's very secure and streamlined and you feel very free because there's nothing covering you or squeezing you except some harness webbing.

I suspect most of what you enjoy about Avelo comes from dumping your typical overstuffed BCD and suboptimal AL80 for a minimalist setup. Something you could also do by switching to a basic BP/W and steel tank for a fraction of the cost and with none of the drawbacks of Avelo.

 

[nadwidny]

The flip side is also true. As you know, a CCR diver typically has 3 airspaces to manage (not counting your lungs). After my certification (i.e., still at the conscious competency stage on CCR), it was SOO nice/easy doing an OC dive with "only" 2 airspaces (wing/drysuit).

The lungs on a CCR diver are part of the loop with the counterlungs and so are part of the 3 airspaces (assuming a drysuit diver). OC also has 3 airspaces as the lungs are a 3rd airspace. Difference between OC and CCR is that the lung airspace volume changes and can be controlled with each breath on OC whereas on CCR you can't do that. That's why it's easier to maintain neutral bouyancy on OC

 

[EdMcNeill09]

Have you ever dived or taught anyone using a steel BP with compact wing and an HP100 or HP80? The weight is very close to the full Avelo system as most people need little if any additional lead. It's very secure and streamlined and you feel very free because there's nothing covering you or squeezing you except some harness webbing.

I suspect most of what you enjoy about Avelo comes from dumping your typical overstuffed BCD and suboptimal AL80 for a minimalist setup. Something you could also do by switching to a basic BP/W and steel tank for a fraction of the cost and with none of the drawbacks of Avelo.

My first BCD was a Halcyon with a steel plate. My first tanks were HP100s. So yes I have dived a similar setup. My current BCD is steel xDeep Zen. My current tanks are Al 80s. I also have a Scubapro Hydros but only dive it under duress. I learned to dive in Monterey in 50 degree water wearing a 7mm farmer John and a 7mm beavertail. I was warm. I looked like the Michelin Man but I was warm and needed 30lbs of lead in addition to my steel HP 100 and my Steel Halcyon. I later got a DUI drysuit and still needed 30lbs of lead. I have around 1500 dives on my steel Zen but have not dived it with a HP 80 though. That would be interesting to try. Am I right in thinking that I would drop about 6lbs of lead switching from a AL 80 to a Steel HP 80? I recall it being around 8lbs going from an AL80 to a Steel100.

Diving Avelo is sublime. It is extremely streamlined and the stable range of Neutral Buoyancy is amazing. I can run the pump and go down 100+' and still be neutral. I can ascend to my safety stop and still be neutral.

 

[jakeluther]

Iv Been diving the avelo for a few dives now. And honestly, i will use it every opportunity i get.

The whole weight thing honestly didn't really change for me. i still needed to add 4kgs to the system, when with a bcd and steel tank i dive 6kgs.

The biggest thing is the buoyancy control. its incredible. As you change depths you dont need to worry about dumping or adding air into your BCD. This is where the 'Gas' savings come into play. not having to use the air in your tank to control your buoyancy gives you more bottom time. Not to say you dont need to be aware/Mindful of what you are doing. But honestly i think its much safer as you reduce the risk of rapid descents.

With the gas savings of not having to worry about inflating and deflating a BCD, along with my 270 Bar starting pressure to allow the first pump to make you neutrally bouyant (which raised the tank to around 290bar) Iv noticed my bottom times going from 45mins, and gaining almost another 30 mins.

It is also extremely streamlined, i found it very easy moving through the water with this system.

It takes a bit of getting used to but after a couple of dives the whole thing becomes natural. Another thing to get used to is you dont have a bladder holding you in a position so you can roll about a bit more which once you get comfortable you will control this.

When running with the scubapro computers with the AVELO mode. Once you get to your depth, and your neutally bouyant once youve done the first pump. when you hit the bookmark button. thats when the computer calculates your remaining bottom time. so even when you pump more water into the tank, the computer is doing the calculation of how much air is remaining even though technically your pressure is increasing. Overall its extremely clever.

Would i purchase this system for myself. Absolutely!

 

[-JD-]

When running with the scubapro computers with the AVELO mode. Once you get to your depth, and your neutally bouyant once youve done the first pump. when you hit the bookmark button. thats when the computer calculates your remaining bottom time. so even when you pump more water into the tank, the computer is doing the calculation of how much air is remaining even though technically your pressure is increasing. Overall its extremely clever.

That is a really good point, I can se the potential for this to "confuse" AI computers. My first (partially caffeinated) thoughts are there isn't a straightforward way of dealing with it for all circumstances since tank pressure has been decoupled from just usable gas and there is an an additional independent dimension of unknowable volumetric variance.