Inflation bottle on Hollis 100 / What am I doing wrong?

[stretchthepenn]

I've set up a drysuit-and-wing inflation bottle on a Hollis 100 for diving SM, and I'd like to get The Hive Mind's feedback.

Here's the scenario: I'm diving a Choptima rebreather, and on an upcoming deco dive to the bottom of a quarry (water temp ~48F), I'm going to be using trimix in sidemounted LP50 cylinders. My BCD is a Hollis 100D with Edd mods. Because reasons, my BCD inflator comes off the right side and ends at my right-side sternum strap.

Due to the poor insulating properties of trimix and the cost of helium, I'd much rather not use trimix for inflating my drysuit. I have the choice between using a 6cf inflation bottle and a 13cf bottle; I'm leaning toward the larger bottle because if I'm going to be inflating my suit with an external bottle, I might as well use it to inflate my BCD, too.

I've set up a system that I think will work and would like y'all's feedback on it.

(Explanatory notes:

• The curled LP hose on the left is for my drysuit inflator.
• The LP hose across the back is the appropriate length for the BCD inflator.
• A can light with its cable routed to the left will mount in the bottom-most black bungees; a suit heater battery will one day mount in the top-most black bungees.
• The inflation bottle's valve is on the left because the Choptima's O2 valve is on the right; they should counterbalance each other.)

Does this setup look reasonable?

Should there be an anchor system of some kind to keep the bottle from pitching forward on descent?

How might I improve the layout/attachments?

 

[grantctobin]

Lot to unpack here.

-I would not recommend running both inflation sources off of one bottle
-If that you’re going to do this, I would not run the wing inflator LP hose over the back of the wing as you have pictured. Run it under the plate and then up the side.
-Does your inflator reg have an OPV on it? It must.
- Because the AL13 attachment point is narrower than the band clamps, the bottle is going to swing left and right. Clip it to the rings and bring the jubilee clamps narrower
-You probably don’t want your eventual heater back that high on your back. Not only is it an entanglement hazard, but I’m skeptical you can reach it.
-I’d remove the second inflator entirely and cap the bladder.
-The AL13 is going to float as it empties. You’ll need to find a way to secure it to your crotch strap or run a bungee over it. It will still rock left, especially as it is currently clipped.
-Most importantly, what were you taught in class or who taught you CCR trimix this way?
-Run your wing off one of your SM bottles. You shouldn’t need much gas in it anyway.

Honestly, I think you need to toss the harness in its entirety and pick up a Katana2 or an LS or a Rec. If you’re not in a situation where you need sidemount (and having all of those things stacked on your back probably means you aren’t), get a set of doubles and use that. You’ll then have appropriate places to put things. Trimix diving in sidemount is a pain, trimix diving in cold water in sidemount is worse if it’s not the right tool for the job. How many decompression bottles are you bringing? How are you mounting and organizing those?

 

[InWay2Deep]

Lot to unpack here.

-I would not recommend running both inflation sources off of one bottle

and the reason is you just lost your redundant backup. Run LPI and DrySuit from 2 independent sources and then you have complete redundancy. Then go w/ the smaller bottle until you find you need more gas.

 

[broncobowsher]

Drysuit bottle of air, you stay warm
Wing gets mix, it doesn't care about thermal conductivity.
Split sources keeps redundancy.

Actual placement and hose routing, can't help there. Never tried a drysuit bottle when I had the SMS100. I did mount an AL40 on the back with an STA a couple of times. Held it reasonably well. Probably not the best solution.

The drysuit bottle will need an OPV on the 1st stage. Normally a 2nd stage reg would handle those chores (relieving the pressure as you ascend) since the 1st stage did its job in keeping a fixed IP over ambient. As you go up, ambient drops, you are not using any gas, absolute pressure in the lines stays the same, so pressure delta increases. OPV vents that.

What dive profiles are you planning on running with this? I have found a 6cf drysuit bottle pretty good sized even for deeper dives. I do keep a fairly square profile typically. Often getting a couple dives on a single fill. I had a 13 and never used it. Eventually selling it to a friend who wanted it for a pony.

 

[stretchthepenn]

Thanks for the replies. I think I'll go with the AL6 and mount it in the upper bungees. It should fit...

My inflation reg is designed for argon, so it has an OPV built in.

 

[grantctobin]

Thanks for the replies. I think I'll go with the AL6 and mount it in the upper bungees. It should fit...

My inflation reg is designed for argon, so it has an OPV built in.

Can you reach it to turn it off underwater?

 

[broncobowsher]

Can you reach it to turn it off underwater?

With a run away drysuit inflator (failure point here) pulling the quick connect off would be faster than turning a bottle valve. I wouldn't worry about it much. So long as diving a squarish profile you only really need it for descent. You can get back without it.

Cave profiles, refer to your cave training.

 

[grantctobin]

With a run away drysuit inflator (failure point here) pulling the quick connect off would be faster than turning a bottle valve. I wouldn't worry about it much. So long as diving a squarish profile you only really need it for descent. You can get back without it.

Cave profiles, refer to your cave training.

Not a chance. He’s in open water in dry gloves in the cold. If anyone can manage to pull that off before it freezes connected they’re a lucky SOB. Don’t put bottles that are on and connected to your person in places that can’t be readily reached, cave or not.

 

[grantctobin]

Not a chance. He’s in open water in dry gloves in the cold. If anyone can manage to pull that off before it freezes connected they’re a lucky SOB. Don’t put bottles that are on and connected to your person in places that can’t be readily reached, cave or not.

And even this ^ totally ignores that he has to reach between his rebreather and his person, with dry gloves and rings, to even get to his inflator.

 

[stretchthepenn]

Post-dive report: The 6cf bottle wouldn't hold pressure (a topic for another thread), so I used the 13cf. I removed the BCD inflator hose, moved the clamps inward, clipped the bottle onto the doorknobs, and tied down the bottle's center with a loop of medium bungee. It worked fine.