Interesting approach to automatic Buoyancy at DEMA

[yle]

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.

Yeah, this is where the new idea makes no sense.

Current standard: an air bladder -- simple, but could fail to either fully deflate or fully inflate, both of which we have simple and established procedures for a remedy (drop weight, disconnect inflator hose.)

The new idea: a pump to add or remove water from a tank for ballast -- complex, could fail either way (pump cannot remove water from tank, or pump is stuck open and fills tank with water), but there is no established (i.e. taught in OW class) procedures to remedy either.

Ummm... why? This reminds me of I new diver I met years ago who was determined to have the fewest hoses possible on his regulator. So he bought a BCD with an alternate air source integrated into his inflator, and a wireless transmitter for his wrist computer. This way his regulator had only two hoses: one for his first stage and one for his inflator. I pointed out to him that having a backup pressure gauge -- should his transmitter fail during a dive -- is a good idea. He didn't want to add another hose, so he got a small pressure gauge that screwed directly into his first stage (like might be used on a stage bottle.) I stopped trying to offer him any useful advice because his primary focus was on using the fewest hoses and not on assessing -- and responding to -- his needs while diving. Just weird.

 

[yle]

Oh goodness. This is from the Avelo website:

"When you swim with the Avelo System, you move. When you stop swimming, you hover. It’s an underwater stability sensation that cannot exist with standard scuba systems today."

(Emphasis added by me) I don't know. Seems like that claim is a little much. I'll leave it at that.

 

[Jcp2]

Yeah, this is where the new idea makes no sense.

Current standard: an air bladder -- simple, but could fail to either fully deflate or fully inflate, both of which we have simple and established procedures for a remedy (drop weight, disconnect inflator hose.)

The new idea: a pump to add or remove water from a tank for ballast -- complex, could fail either way (pump cannot remove water from tank, or pump is stuck open and fills tank with water), but there is no established (i.e. taught in OW class) procedures to remedy either.

Ummm... why? This reminds me of I new diver I met years ago who was determined to have the fewest hoses possible on his regulator. So he bought a BCD with an alternate air source integrated into his inflator, and a wireless transmitter for his wrist computer. This way his regulator had only two hoses: one for his first stage and one for his inflator. I pointed out to him that having a backup pressure gauge -- should his transmitter fail during a dive -- is a good idea. He didn't want to add another hose, so he got a small pressure gauge that screwed directly into his first stage (like might be used on a stage bottle.) I stopped trying to offer him any useful advice because his primary focus was on using the fewest hoses and not on assessing -- and responding to -- his needs while diving. Just weird.

I'm under the impression that one SPG, either analog or AI, is okay for general open water diving. Do you have two analog SPGs on your set up in case one fails?

 

[yle]

I'm under the impression that one SPG, either analog or AI, is okay for general open water diving. Do you have two analog SPGs on your set up in case one fails?

Any number of pressure gauges is okay for OW diving. Everyone gets to decide the level of risk -- or simply inconvenience -- in the event of a gear failure that they're willing to accept.

In my story, please note that I didn't tell the newish diver that he must have a second pressure gauge, that it's some kind of rule and he has to do what I say. I simply made the suggestion that it was something he should consider, because it's a good idea. Personally, I'm a fan of simple mechanical gauges. I've used the same SPG for over 1000 dives in the past 10 years, never a problem. But in that time I've seen others have transmitter and battery problems regularly (not a lot, but enough to convince me that I don't need it. My wrist computer has AI, but I don't have the transmitter.)

So no, I do not have two analog SPGs on my regulator. And if people want to use just one gauge, whether mechanical or digital, wireless or whatever -- entirely their call. The point of my story was that when I suggested a mechanical gauge as a backup, he agreed it was a good idea... but then used a small gauge that he wouldn't be able to read on his first stage because he was so obsessed with having only two hoses.

Thanks for asking, hope this helps.

 

[broncobowsher]

... They said they often dive this to 150ft for, with a 50CF of air??

Have you ever heard of a 'bounce dive'?

 

[scubadada]

I will drive down to Key Largo and take the Recreational Avelo Diver specialty when it starts at Horizon Divers. I believe I read that the RAD specialty course (online, in person, and 2 dives) will cost $450, correct me if you find different. I paid nearly that to do my try rebreather course/dive with Divetech in Grand Cayman in 2007. I did not go on to dive rebreathers but really enjoyed the experience. Not sure if I would/could go on to dive Avelo, but looking forward to trying it.

Avelo says Sept/Oct, have not heard from Horizon.

So, Horizon Divers decided not to be an early adopter of the Avelo system. Dive with Harmony on Maui was lost in the fire.

Currently, there are 3 Avelo dive centers, one in Australia, one on Catalina in California, and Dive Friends on Bonaire Avelo - Dive Centers

My wife and I plan a return to Bonaire sometime this fall and I will probably do the certification and a few dives at that time. We aready use Dive Friends.

 

[lowwall]

So, Horizon Divers decided not to be an early adopter of the Avelo system.

It would be interesting to know why.

Getting back on topic. There's something I noticed on the Divers Ready video that's been nagging at me. James said the only time he ran the pump (decreasing buoyancy/adding weight) was at the start of the dive to get under and at 2/3 pressure to compensate for the gas used. He did nothing to change buoyancy at the end of dives, going from 100' to surface without touching anything.

He was wearing a wetsuit in the video. It was South Florida so likely a 3mm. Here's the part that's been bugging me. The physics haven't changed, even though there's no air bubble in a wing that needs to be compensated for, you are still using gas which will make you gradually more buoyant and your wetsuit will obviously change in buoyancy as your depth changes. So why aren't these divers having to fiddle with the pump more often, especially on the ascent?

I think the answer is that everyone who has tried this so far have been very experienced divers, and mostly instructors at that. These are people who can handle a couple of kilos of buoyancy change with nothing more than breath control. I don't think you'd have the same result with less experienced divers. Either there's going to be a lot of fiddling with the buoyancy during the dive or the usual beginner solution of extra finning to overcome being non-neutral (with the resultant increased air consumption). The ascent is going to be especially problematic since adding weight is such a slow process with this system. I suspect they'll have a very high percentage of blown safety stops until they figure out a way to address this in training.

I also think they should not allow the use of this with anything over a 3mm neoprene wetsuit.

 

[tridacna]

DEMA 24 is approaching. Be interesting to see if they are there again. Will be testing their seed capital for sure. Don’t see too much in sales yet.

 

[mac66]

FYI...Dive Friends in Bonaire is advertising Avelo.

 

[scubadada]

FYI...Dive Friends in Bonaire is advertising Avelo.

Aviad Cahana, CEO Avelo, will be teaching the courses Sept 13-17. I'm sorry I could not do those dates.