Question Is it normal for a doubles wing to feel like a 'pillow' behind your head when in trim?

[justinthedeeps]

I am experimenting with the different holes on my wing and I'm curious, is it suppose to feel like a little 'pillow' in the bottom-back of your head when looking forward and in-trim? I can still reach my valves and hoses of course. If I mount my wing lower, I worry my main corrugated inflator elbow gets too close to the tanks and makes contact while also my redundant inflator is basically touching the side of my steel plate. When stepping off the boat or walking around, I worry this could potentially damage the elbows causing a failure. Are these concerns valid or am I overthinking things?

Your wing should never be a pillow, since you want to reduce the weight you're carrying until the wing is not very full while diving. Then the excess buoyancy will be there in case you need to relax on the surface or compensate for the compression of a thick wetsuit at deep depths, which is the only time you should really have much air in there.

 

[inquis]

It sounds like you're somewhat arbitrarily moving things around hoping to land on a good combination at some point. You might consider a 2-step approach: 1) arrange for good/stable trim with near empty tanks and empty wing. Move lead, shift tanks, etc., all while still being able to manipulate valves. Then 2) position the wing to yield that same trim using full tanks. This will give stable trim throughout the dive, avoid over-weighting, and I suspect the backup elbow won't be smashed against the plate.

On the flip side, it may not be possible to do #1 with an empty wing. Tech gear can be... heavy.

 

[Dirt Pineapple]

It sounds like you're somewhat arbitrarily moving things around hoping to land on a good combination at some point. You might consider a 2-step approach: 1) arrange for good/stable trim with near empty tanks and empty wing. Move lead, shift tanks, etc., all while still being able to manipulate valves. Then 2) position the wing to yield that same trim using full tanks. This will give stable trim throughout the dive, avoid over-weighting, and I suspect the backup elbow won't be smashed against the plate.

On the flip side, it may not be possible to do #1 with an empty wing. Tech gear can be... heavy.

I am pretty negative at the start of the dive with full A80 doubles. Being negative is making me have to inflate the wing a little more than normal. This is no matter what whether it's mounted higher (acting like a pillow to avoid tank/plate contact with elbows) or mounted lower.
Should I not start the dive fairly negative though? If I start neutral, I'll be super positive during my stops, right?

 

[Lorenzoid]

I am pretty negative at the start of the dive with full A80 doubles. Being negative is making me have to inflate the wing a little more than normal. This is no matter what whether it's mounted higher (acting like a pillow to avoid tank/plate contact with elbows) or mounted lower.
Should I not start the dive fairly negative though? If I start neutral, I'll be super positive during my stops, right?

You start the dive negative by the weight of the amount of gas you're going to use during the main portion of the dive, and then by the time you reach your stops you're neutral with almost no air in the wing.

 

[-JD-]

So it's not that high up to achieve flat trim, it's more so me experimenting with different configurations. This one with the wing high up was because I previously had it mounted lower to the point where the inflator elbows looked like they were getting crushed by the tank and by the plate (redundant inflator elbow).

I use the Dive Rite Rec XT, the front inflator elbow is pretty tight to the steel plate.

I just grabbbed my Dual-Bladder Rec-XT wing and put it on both my Dive-Rite LW-Stainless and OMS SS plates.

With the highest hole in the wing aligned with the lowest hole on the plate - i.e. worst case ....

• The primary bladder elbow assy. is above the top of the plate so can't be crushed between the plate and tank.
• The secondary bladder elbow nests just alongside the edge of the plate, so unless one is careless slamming the twinset in place with the wing being misaligned during assembly, it is fine.

I don't have my dog-bone plate handy ATM, but I dove the 2022 Invasion with the DB Rec-XT and dog-bone with no issues.

Your plate may be different, of course, but the OMS and Dive Rite are pretty typical of the ones I've seen.

I am pretty negative at the start of the dive with full A80 doubles. Being negative is making me have to inflate the wing a little more than normal. This is no matter what whether it's mounted higher (acting like a pillow to avoid tank/plate contact with elbows) or mounted lower.
Should I not start the dive fairly negative though? If I start neutral, I'll be super positive during my stops, right?

An AL80 holds about 4lbs of air so your twinset should lose 8lbs from full to empty. So "Ideally" you would start the dive 8lbs negative with an empty wing. I'd generally give myself a couple lbs of margin and aim for say 10lbs negative splashing and 2lbs negative at my stop to allow for some un-evacuated air.

 

[justinthedeeps]

Go diving until you have about ~30 bar or ~500 psi left in all of your back-mounted tanks. Find a spot where the water is no deeper than ~5 metres or ~15 feet. Dump all of the air of the wing. Double check it's totally empty. Completely stop kicking or moving your legs. Then start removing weight. Most people who haven't done this test yet can drop a couple of lead bricks on this test, sometimes more.

 

[inquis]

Being negative is making me have to inflate the wing a little more than normal.

If you're neutral with empty tanks & wing (I think you missed that part in what I wrote), you absolutely will be negative by the amount of gas in the tanks when they're not empty.

The 2-step process eliminates the effect of the wing from your trim, making for a simpler process. Once you have the (nearly) empty tank case handled, it's easy to extend to the full-tank case: the only thing you need to mess with is the wing position, and it is obvious when it's not in the right place.

 

[happy-diver]

Where are your bands positioned, do you want me to send you some film for your camera, dude

I worry

 

[rongoodman]

Where are your bands positioned, do you want me to send you some film for your camera, dude

What is this "film" you speak of?