Question Bigger single tank wing. DiveRite Voyager EXP not enough lift.

[Ty Hamby]

Wearing 30 lb of lead, might be a little high, but it also depends on how fat you are and what type of tank you are using.

As others have said, it sounds like you are overweighted, because the suit is not fully compressed at 30 ft. If the BC looked like that at 100, I would not be concerned.

I apologize for not offering more information. The 7mm farmer john is size 4XL. Its a lot of neoprene. I weigh 260lbs. The tank is a HP133. 22lbs in DiveRite ditchable pouches and 8 lbs. non-ditch on the waist strap behind the ditch pockets and on the top tank strap.

 

[gordonscuba]

To answer the easier one of the questions in the OP: a bungee should never be used on a wing. Yes, take off the bungee regardless of the questions about weighting.

 

[johndiver999]

I apologize for not offering more information. The 7mm farmer john is size 4XL. Its a lot of neoprene. I weigh 260lbs. The tank is a HP133. 22lbs in DiveRite ditchable pouches and 8 lbs. non-ditch on the waist strap behind the ditch pockets and on the top tank strap.

30 lbs of lead seems to be in the ballpark of reasonable. I personally would want some lead on a freedive weightbelt, and have some off the harness. That change alone might solve your primary concerns.

 

[Wibble]

Weighting is about two things

There’s two factors in correct weighting: fixed weight and variable weight. Fixed weight is the amount required to sink you and your complete rig with full tanks.

Variable weight is the weight you loose during the dive (i.e. gas consumed) and weight differences at depth (your wetsuit compression). You should also factor in items you use such as a heavy reel for an SMB.

Gas weight is important especially if you have a large tank, which you do. You use up to 133 cubic feet of air. This weighs 36 grams (or 0.08 of your “pounds”), so you need to have 133 x 36g = 4.8kg (which is 10.5 of your “pounds”).

As you can use this gas, you must add an additional 5kg or 10 lbs to the weight when you drop in with and you need to compensate with the equivalent buoyancy in your BCD.

As you descend, you also need to add some more gas in your BCD to counteract the loss of buoyancy in your wetsuit. Can’t find a reference for this weight change.


Bottom line. You are definitely overweighted underwater if you’ve filled your BCD to fire the OPV (over pressure valve).

The only gas you should have in your BCD underwater is the variable amount to compensate for your gas weight and your wetsuit buoyancy changing at depth.

 

[Ty Hamby]

Bottom line. You are definitely overweighted underwater if you’ve filled your BCD to fire the OPV (over pressure valve).

The only gas you should have in your BCD underwater is the variable amount to compensate for your gas weight and your wetsuit buoyancy changing at depth.

The one time I hit the OPV was when doing my Deep SSI cert. As we transitioned through 80 to 100. I was adding air to slow my decent when the OPV burped. As I began to slow too much I quickly began dumping air to continue my decent. We as a group sat at 100 and did some cognitive tests for a few minutes and then began our ascent. That was the only time I ever bumped up against the OPV. I hope this is more clear. I am not constantly blowing the OPV. I just was close to it at 100. I only hit it because I added more air than needed. This still has me wondering if this Voyager EXP wing will safely work below 100 with this suit and heavy tank. I am not sure. I am headed out next week to the Peace liveaboard. I will keep pulling weight each dive until I struggle get down and add back when I struggle to stay down at the end of the tank. This tank goes slightly positive at the end.

 

[inquis]

As you descend, you also need to add some more gas in your BCD to counteract the loss of buoyancy in your wetsuit. Can’t find a reference for this weight change

Wikipedia summarizes some empirical studies, but the reduction factor is fairly close to 1/ATA. At 30 ft (1.9 ATA) that factor would be about 0.52, but one should be neutral around 15 ft (*) where the reduction factor is 0.69. That means the wetsuit compression from 15 to 30 ft -- that which is compensated by the wing -- is 17% of the surface buoyancy. The surface buoyancy of my single-layer 2XL Bare Reactive 7mm is about 16 lb, so I'd expect a 4XL farmer john + jacket to have a surface buoyancy of about 1.5x (24 lb). The wing would need to compensate for 17% of 24 lb or about 4 lbs.

Add on the gas weight of 133 cuft (10.6 lb) less about a pound of reserve air and the wing needs to compensate for about 14 lbs (gas & suit compression combined). A 35 lb wing should be less than 2/5th full at 30 ft when the diver is properly weighted. Even at 100 ft, that 35 lb wing should be less than half full.

(*) Note: some will weight to be neutral at 10 ft to avoid corking during the final ascent in a really thick wetsuit. Even still, their wing should be less than half full at 30 ft.

 

[inquis]

Tip: one can measure the surface buoyancy of their wetsuit by putting it in a submerged pillowcase (avoid trapping air while doing so) and adding lead until it sinks in a pool, hot tub, or even a water-filled trash can or recycle bin. Even easier is to add enough ballast to sink it and measure the just-submerged bundle using a luggage scale with and without the suit. The difference is the suit buoyancy. (I used an old vice I had laying around as I didn't have enough lead.)

 

[Umuntu]

Advice is appreciated.

This is a useful resource to use:

Info Thread 'Optimal Buoyancy Computer'

Mar 23, 2019

The Optimal Buoyancy Computer
A tool to help nail buoyancy and improve safety, before you splash​

1) How much lead should I carry with my new wetsuit?
2) How big a wing should I buy?
3) Will my BCD support my lead, both at the surface and when my wetsuit is compressed at depth?
4) Will my BCD support my rig without the help of my wetsuit/drysuit, if I doff it at the surface in an emergency, or underwater due to an entanglement?
5) How do I balance my rig?
6) How might partial weight ditching help me deal with an emergency? Will it really result...

• rsingler
• balanced rig buoyancy ditching neutral buoyancy
• Replies: 171
• Forum: ScubaBoard Knowledge Base

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[happy-diver]

One thing, of ten things, interesting about scuba, is when divers jump off a boat with their wing inflated
follow gravity weight and momentum under the water which is the point of diving only to burst back up
to the surface or even a foot above the surface to bob around talking to the other people from the boat
that they have already been talking with on the boat waiting for people still on the boat too busy talking