EdMcNeill09
Contributor
Short answer: probably, but I suspect for reasons other than what you're thinking based on your post.
Details:
At the beginning of the dive you would want to be positively buoyant by +2 lb. Assume this is possible. If you consumed all the gas in the Avelo tank, there would be room for an additional 9 L of water or 20 lb of ballast (ignoring the space the bladder takes up for simplicity). That's the equivalent of about 250 cuft of gas you could conceivably take with you and consume while still remaining neutral.
The difficulty lies with that initial assumption. For the normal Avelo system, the "fixed parts" (cylinder/plate/pump/batteries/lead/diver) have some buoyancy (call it X1), and we know the total buoyancy will be +2 lb. Since X1 - 6 lb (Avelo gas weight) = +2 lb, we see that X1 = +8 lb. If you add an AL80/reg, the fixed buoyancy will increase by +2 lb (assuming +4 lb empty tank in salt water - 2 lb reg), so X2 = +10 lb. The total buoyancy will then be: B2 = +10 lb (X2) - 6 lb (Avelo gas weight) - 6 lb (AL80 gas weight) = -2 lb.
That's a problem, but possibly not insurmountable. If you had added lead to the system, you could just remove 4 lb of lead, and you're back to your target +2 lb starting buoyancy. Enjoy the additional bottom time and watch that NDL.
If you didn't add lead (e.g., you are diving without a wetsuit), what do you do? Avelo already solved this issue by making "buoyancy pads" (I believe out of plastic) that can be attached to the system to increase its buoyancy. (Search upthread, and you'll run across mention of them.) The crucial question is whether those pads can add 4 additional pounds of buoyancy. You're looking at a volume increase of at least the size of a 2L soda bottle (not even counting the weight of the plastic). I have no idea how much buoyancy those pads add or how many attachment points are built-in.
Another option might be to use a more buoyant tank. Connecting the dots, you may guess this is why Avelo chose the carbon-wrapped cylinder in the first place. It wasn't just for the "cool factor".
Bottom line: I believe a side-mounted AL80 would work with Avelo in most cases. Weighting will be CRITICAL to safety and successful usage, but that's already the case for the normal system.
I haven't actually weighed an Avelo System but can assure you that it is way lighter than Standard Scuba, not least as you carry much less weight for buoyancy.I see three possible conclusions:
1. It's a corporate oversight. I can see a reasonable, if somewhat far-fetched explanation of some overzealous corporate stooge deciding this is important information that must be kept secret to avoid competitors ripping their product or something, or just straight up not realizing this is information divers would want/need. The big issue with this is, going by the video that was posted here, the founder is a diver, and would know that weight and buoyancy (and therefore volume) is a huge selling point to divers. Perhaps he's handing the marketing/information management off to a subordinate who's never been diving before though.
2. Perhaps the exact weight/dimensions of the unit changes fairly frequently, as newer materials, better batteries, smaller motors, etc. are incorporated into the design. Thus, there's "no point" in publishing a weight estimate that would soon become out of date and misleading. Credence to this is that, if you look at the Avelo total product weight from early in this thread vs now, the overall weight estimation of Avelo went up five pounds. Perhaps they wish to avoid such changes as much as possible. The major issue with this is that the total system weight has changed only once to my knowledge, therefore implying that such changes are in fact, rather rare.
3. They have something to hide. Perhaps they want to make it difficult for people to make direct, one-to-one weight comparisons of their current rig to Avelo. If I knew, for example, the exact buoyancy of an Avelo system, I could compare it to my own system to determine the lead I could lose, and from there come up with an exact weight differential between them, which might be less favorable than Avelo indicates on their marketing material. Supporting evidence for this is the rather impressive 75 lb weight estimate they give the typical scuba diver on their site, and the fact that, as I've said several times before (and still not received a good explanation for) Avelo actually increased their estimate of the average diver's kit weight by 5 lbs when Avelo's system weight increased, so that the difference remained 30 lbs despite Avelo being five pounds heavier than it was before. Note that this motivation isn't simply "Avelo is lying about their product being lighter" and more "Avelo is providing a product that aims to reduce weight, and benefits from you not being able to do the math and say 'eh, five pounds isn't really worth the trouble.'"
Please note that I do consider any of these three motivations, a combination of all three, or some secret fourth motivation I haven't thought of to be entirely plausible. I still find the change in the average diver's weight from 70 to 75 lbs on their site to be extremely suspcious, and would love an explanation of that. Like, please people, I think this is a cool product. I'd love to see what they'll make of it in five or ten years. If the price point ever comes down enough, I might even buy one. But the math kinda ain't mathing on some of these claims.
And like, seriously. On a diver charter in Ha'waii, I dove a rental jacket style bcd with standard AL 80 and normal regulator. All were scubapro brand gear. The 80 weighed 35 lbs, as is standard. I don't remember the exact BCD, but it was a decently high end scubapro, not one of those mass market "shop only" BCDs some companies allegedly make, and the heaviest scubapro jacket style BCD I found on their site was 10 lbs. I had 10 lbs of lead. The reg probably weight 2 lbs at the most. So, overall weight: 57 lbs, on the high estimate. This is 12 lbs above avelo, at the very most, and not the 30 lbs their site advertises.
Now, this is a decent amount of weight to save, and almost all of the savings are in lead I can now ditch, which is wonderful because adding something heavy to my kit which already weighs too much has always been frustrating...but why can't they just say 12 lbs of weight saved? Or give a range of 6-18 lbs or 12-20 lbs or whatever. Saying you save thirty pounds feels extremely cherry picked at the best, and at worst, does make me question the validity of their product overall. I don't know of any diver that's not using an unnecessary amount of lead with a 75 lbs single tank warm water rig.
Let me reiterate. I like the product. I'd happily try it, if doing so did not require traveling far, far away from where I live and spending several hundred dollars I don't currently have to spare. I would love an explanation of why the weight numbers don't add up. I'm just pointing out issues here people.
For example a full aluminum 80 weighs 40lb give or take a few ounces. A L ScubaPro Hydros is 11.75 lbs. A MK25 first stage is 2.65 lbs with a primary. Add hoses an Octo, and an SPG and you're probably 4-5 lbs lets call it 4. Now we're at around 56 lbs before we add weights. When I dive a Hydros I need 14-16lbs depending on my wetsuit. So for me a standard setup is right around 70 - 72 lbs. Currently when I dive Avelo I need 3lbs of lead. In another couple of months my wetsuit will have deteriorated a bit more and I won't need any weight when diving Avelo. So Diving Avelo saves me around 20 - 25 lbs. That is pretty significant. I definitely feel the difference when I climb the ladder back onto the boat.
Every diver is different though and weight needs differ dramatically.
I won't comment on the changes in published weight of an Avelo system. I've no actual idea. But I would point out this is a startup company with a lot of moving parts. It's also a high integrity company that would not intentionally mislead or misinform.