Weighted STA and 36# Pioneer?

Just got back from Aruba, 80-degree water, 50-foot visibility, and only a ten-minute boat ride to the dive site! However, for now it’s back to the dark cold quarry. Based on the last trip to Mt. Storm, with the CLX-450 and Andy’s US200 underwear, I want to get some of the weight out of the ACB system. So, I got an extra long pattern Fred-T plate and a Halcyon weighted Single Tank Adaptor (STA). Together the two should add about 10 pounds that I can take out of the ACB.

I’m also starting to think that perhaps 36 pounds of lift is not enough to float the rig with the ACB so I might be better off with a weight belt. Let’s see; PS HP120 (11 pounds), F-T Plate, (11 pounds), STA (6 pounds), Bailout bottle (5 ponds) that’s 33 pounds without the canister light or reel, yeah looks like a weight belt. Any suggestions, other than the obvious yet expensive, get a larger wing?

Tonight I’m going to attempt putting the new parts (Fred-T plate and STA) together with the Pioneer wing for the first time. It looks simple enough, just bolt the STA to the plate with the supplied bolts with the bladder sandwiched in-between. Is it that simple or is Murphy lurking about? Any tips or suggestions?

Thanks,
Mike

MikeS once bubbled...
I’m also starting to think that perhaps 36 pounds of lift is not enough to float the rig with the ACB so I might be better off with a weight belt. Let’s see; PS HP120 (11 pounds), F-T Plate, (11 pounds), STA (6 pounds), Bailout bottle (5 ponds) that’s 33 pounds without the canister light or reel, yeah looks like a weight belt. Any suggestions, other than the obvious yet expensive, get a larger wing?

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You are leaving out the bouyant components of your kit. You float and so does your drysuit. You can subtract that from your total weight. Your drysuit also provides an additional source of lift in an emergency.

Think of it this way:

In my 7mm wetsuit and nothing else, it requires like 18 lbs to get me neutral. So, I start out 18 lbs positive. Then, I add my 6 lb backplate. I'm now at 12 lbs positive. Then I add a HP72 which is 11 lbs negative. Now I still need at least 1 lb just to sink at the beginning of a dive! At that point, I shouldn't need a wing at all. I should be neutral. So, that first 33 lbs is probably going almost all into sinking your body. Depending on your physique and undergarment, you might be like 10 lbs negative at the beginning of a dive, which means you still only need a small amount of air in your 36# wing to get you neutral. If you fill that sucker up, you're going to rocket to the surface.

Your 36# will work fine.

Somebody correct me if I have made a logic error.

AaronBBrown once bubbled...


You are leaving out the bouyant components of your kit. You float and so does your drysuit. You can subtract that from your total weight. Your drysuit also provides an additional source of lift in an emergency.

Your 36# will work fine.

Somebody correct me if I have made a logic error.

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Weight of components dry doesn't mean zip. As you say, you have to look at the total, and when its in the water. Good answer.

MD

AaronBBrown once bubbled...


You are leaving out the bouyant components of your kit. You float and so does your drysuit. You can subtract that from your total weight. Your drysuit also provides an additional source of lift in an emergency.

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Aaron,

As far as I’ve been able to determine there are three aspects to properly sizing the lift of a wing for drysuit diving. First, it must be able provide sufficient lift to compensate for any swing weight, including tank weight (full versus empty) and the negative buoyancy of anything you might drop or handoff (i.e. bailout bottle and wreck reel). I’m O.K. here.

Secondly, the wing should provide sufficient lift to allow you to swim up to the surface in the case of a dry suit flood. Again, I think I’m O.K. here but would likely have to drop weight or deploy my surface/marker at the surface to become positive.

The third issue is what would happen if you take the BP off in the water. With the suggested configuration, approximately 33 pounds negative, and any substantial weight in the ACB system, the rig would sink like a rock if I took it off. I would become very positively buoyant but the rig would sink.

So I think there are two options. Move weight to a weight belt or get a wing with more lift to “lift” the rig if I took it off at the surface. Moving weight to the weight belt would not change the overall weight but would reduce the weight of the rig when taken off at the surface. It would also result in being less positive when taking off the BP underwater, (i.e. disentanglement). Oh no, I think ‘m talking myself into a weight belt!

Mike

MikeS once bubbled...
Secondly, the wing should provide sufficient lift to allow you to swim up to the surface in the case of a dry suit flood. Again, I think I’m O.K. here but would likely have to drop weight or deploy my surface/marker at the surface to become positive.

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Unless your suit fully floods (very rare) and your wing is punctured, you can easily inflate your wing on the surface to provide the small amount of positive bouyancy you'll need. Also, a fully flooded drysuit should be neutral since water has the same bouyancy characteristics as water.

The third issue is what would happen if you take the BP off in the water. With the suggested configuration, approximately 33 pounds negative, and any substantial weight in the ACB system, the rig would sink like a rock if I took it off. I would become very positively buoyant but the rig would sink.

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True, but I'm not sure how you are going to be able to take the harness off underwater when you are already entangled. It's hard enough to get in and out of on the surface when properly fit. This seems unrealistic...solving a problem that doesn't exist.


Wreck divers out here dive with LP120 doubles, canister lights, dry suits and only use a 45-55 lb wing. In your single tank, I'm pretty sure it isn't a problem since you'll likely be close to neutral anyhow. If it's a concern, get a lift bag for a redundant lift source.

If your drysuit floods, it means there is a leak. The leak would have to be ridiculously extreme and high on your body for you to not be able to put some air in it on the surface. Unless the hole is in the upper shoulder, you'll still be able to inflate it some.

Again...someone correct me if I'm off base here.


My question is, why did you get an STA and super-heavy backplate? It sounds like you don't need it. If you are worried about "needing" a weight belt, just take the STA off and stick 6 lbs on your waist. Problem solved.

A local tech instructor emphasizes the need be able to swim/float/communicate on the surface in light chop with your wing inflated (ie: water below your neck).

I'm still making up my mind about whether I agree with this or not.

He states that in order to achieve this goal in a drysuit, bp, steel doubles, deco bottles (which should be neutral, but the regs make them a couple of lbs negative), light cannister, etc. you need at least an 80 lb wing, and a 100 lb wing is best. He pushes the big OMS wings pretty hard.

I have issues with the oversize wings and bungees that accompany them.

I'd love to hear some comments on how valid this is from a safety and practicallity perspective.

Atticus once bubbled...
He states that in order to achieve this goal in a drysuit, bp, steel doubles, deco bottles (which should be neutral, but the regs make them a couple of lbs negative), light cannister, etc. you need at least an 80 lb wing, and a 100 lb wing is best. He pushes the big OMS wings pretty hard.

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I don't dive doubles yet, but....


This sounds like a hot-dog situation...you know...the wing wraps up around the tanks like a hot dog bun.

Now you are horizontal in the water and want to dump air. All that air is up next to (or above) your tanks....How does it get out?

Atticus once bubbled...
A local tech instructor emphasizes the need be able to swim/float/communicate on the surface in light chop with your wing inflated (ie: water below your neck).

Click to expand...

If you do the math, you'll find that this is perfectly doable with a much smaller wing.

AaronBBrown once bubbled...

True, but I'm not sure how you are going to be able to take the harness off underwater when you are already entangled. It's hard enough to get in and out of on the surface when properly fit. This seems unrealistic...solving a problem that doesn't exist.

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I have always wondered about the need to remove your gear UW. I've seen several different opinions on the board. Not knowing better, I'm able to do it if I ever need to.

However, I'm convinced about the need to be able to get in or out of the harness on the surface, small boat diving or a rescue situations being two very obvious reasons. If your rig is negative, that won't be possible and could be a significant problem.

AaronBBrown once bubbled...
My question is, why did you get an STA and super-heavy backplate? It sounds like you don't need it. If you are worried about "needing" a weight belt, just take the STA off and stick 6 lbs on your waist. Problem solved.

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The reasoning for the weighted STA and super-heavy backplate is to remove some of the weight from the ACB. On my last wetsuit dive I had 26 pounds in the ACB with the Halcyon back plate and was still having to hold onto the bottom for the safety stop. I’m guessing that 30 pounds would be about right. That’s too much for the ACB system. I only used 10 pounds in the pool without the underwear and was comfortable so I’m reasoning that the underwear makes the drysuit very buoyant. I’ll have to dig out Fred’s email but I think he said the new plate was about 11 pounds negative versus the 6 pounds of the Halcyon plate. The weighted STA provides 6 pounds of ballast. That means I should be able to reduce the weight in the ACB (or weight-belt) from 30 to a more manageable 18 or 19 pounds.

True, but I'm not sure how you are going to be able to take the harness off underwater when you are already entangled. It's hard enough to get in and out of on the surface when properly fit. This seems unrealistic...solving a problem that doesn't exist.

Now that you’ve made me think about this … the only way I can see the backplate coming off in the water while in the drysuit is with the harness quick release (A.K.A. Sea snips). Still there may be an advantage to having the rig float ... have to think some more about this.

If it's a concern, get a lift bag for a redundant lift source.

I have a Halcyon Big Alert Marker with an advertised 40 pounds of lift and don’t leave home without it.