Latest attempt to deal with sidemount al80 tank trim

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divezonescuba

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So I have been experimenting with different ways to maintain al80 tank trim over the last couple of years. Al80s because that what is usually available thruout the Caribbean and elsewhere.

For various reasons with al80s, I have rejected weighting the tank butts, sliding drings, reattaching the tank from rear to front drings, and the triangle bolt snap method.

In truth, I am in search of a somewhat rigid, set and forget solution with al80s.

My latest system which I have been using for the last six months is to have an opposite mounted bungee which attaches to a dring on each tanks cam band. This provides sufficient tension to pin the tank to my side between the bungee on the front and the rear dring and tail snap on my waist belt.

Although this system keeps the tank in the same good trim position even when the tank goes positive, it is somewhat cumbersome to use initially as I have to stretch the bungee bolt snaps across my front to the tank on the opppsite side for each side. This can be done from a sitting position, but I normally do so during the descent.

I have come up with an alternative solution to doing away with the cross mounted burgees, but have not yet had time to test it. That may come this weekend. The idea is to still use the tail snap on the rear dring, but instead of the cross mounted bungee, to use magnets. Here, a magnet is mounted on the waist belt and another is mounted on the tank band. So the magnetic force of the two parts keeps the tank in place. As before I use a ring bungee system with a bungee tank neck choaker for the nose clip.

The major advantage of this concept is that the tank will automatically position and magnetically latch itself at the beginning of the dive as the tank is negative at that point. Thus, no intervention or repositioning is required thru out the dive.

I will post the results of this experiment after I have had a chance to properly test it.
 
While I’m all for innovation, this seems like a mess of a solution to a problem that doesn’t exist that should have been solved in training. Use two sets of narrow d-rings on each side of the waist belt and adjust from rear to front ring at the turning point. With practice, it’s brainless and requires no physical exertion.

If you’re hellbent on this and not using more than two bottles, add a second bolt snap to your hose clamp/cam band and clip one fore and one aft with little to no leash and it’ll stay in place.

Ring bungees are your other issue.
 
What's the problem with sliding rings, or just a second ring to move the clip to as the tail gets light?
 
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I have found when using AL that not all are created equal. I have used some that become tail light at 2500 to 1900.
Being aware of what’s going on and using a sliding d-ring or a low profile front ring works.
 
Actually, I dispensed with the sliding dring and front an back dring approaches years ago.

The ring bungee and bungee choaker system works great and is far superior to any plain bungee system / bolt snap / double snap system.

Weakness of the plain ring bungee systems are eliminated with the bungee choaker.
 
I am having a hard time visualizing this technique. It sounds so complicated and yield no better result than moving the tank to the forward ring
 
Definitely a solution in search of a problem, and a rather elaborate one at that. You're already putting the tanks out of position by using ring bungees with chokers, so now you're inventing an elaborate system of gears and pulleys and magnets and flux capacitors to solve a problem that the best sidemount divers in the world have already licked with independent loop bungees and sliding/two d-rings in far more austere situations.

I can't see in any way how your solution is superior to the bog standard AL80 sidemount paradigm, but I also think that there's nothing wrong with screwing around for s'n'g's, so drive on, "advantage" being in the eyes of the beholder I guess.
 
I am having a hard time visualizing this technique. It sounds so complicated and yield no better result than moving the tank to the forward ring

It is. It tends to go along with people who think ring bungees are the way to go. But hey, pontoon boats can be fun too. They end up looking like this:
WRONG PICTURE> PLACE HOLDER UNTIL I CAN FIND THE ONE I WANTED.
 
try having the bungee leash clip to your crotch d-ring instead of going across from one tank to the other. Gives you a pair of bungees instead of a single one, but it should be much easier to manipulate.
 
https://www.shearwater.com/products/teric/

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