Wing lift?

[Roman_66]

25 maybe a bit exergerate, but a new wetsuit like a Aqualung SoAflex 8/7mm can easily be 20lb positive on surface. I can have a 10lb weight belt on me and still float with head above water.

Agree : with new 8mm wet suite you might need wing 40lb and 30lb might be not enough. It is correct in case suit loosing buoyancy more than 20 lb.
Anyway, proper weight check with 500 PSI tank will provide the correct answer.
I like my full 1mm ScubaPro and do weight check with it in most of my configurations.

Storker, I agreed above that catastrophic dry suit flood may cause to additional 10lb negative buoyancy , or even more in case thicker underwear.
But even in this case you have from 5 lb (AL80) till 8 lb (HP120) air negative buoyancy + 10-14 suddenly negative buoyancy from flooded dry suite + 2-4 lb planned overweight. Still total 26 lb and wing 30 lb, more than enough even for emergency situation and diver doesn't need to ditch any weights.

 

[Bob DBF]

Agree : with new 8mm wet suite you might need wing 40lb and 30lb might be not enough. It is correct in case suit loosing buoyancy more than 20 lb.

I Abalone dive in a 7mm farmer john, wear 27# on my belt, and am neutral around 35' or so when freediving. The suit will compress some more if I were to go deeper, but it is harder to define how much when on SCUBA. My 40# seems to work fine so far.



Bob

 

[Manta Man]

two things factor into buoyancy, the rig, which is more negative with a full tank than it is empty by up to 12lb swing depending on size of the tank. LP104 is one of the biggest and most negative tanks, and is almost 16lbs negative when full. So using that
16lb tank
3lbs regulator
up to 11lbs for a bp/w *6lb plate, 2lb STA, 2lbs of cam bands, then about 1lb for d-rings, the webbing, and buckle
there's 30lbs right that, and that's just the rig. This is obviously worst case scenario

Dive is now wearing a 7mm farmer john because it's cold and they can't afford a drysuit. Those can be up to 40lbs buoyant. So you take of 15lbs from that because of the tank and bp/w, and you still need 25lbs of lead to sink. At the surface the wing is only keeping the 15lbs of the tank plus 12lbs of your noggin up, so it will be mostly full, but still able to keep you at the surface.

If the diver is diving shallow, they might be able to get away with a 40lb wing, but if they're diving any deeper than 70ft or so, a 40lb wing isn't actually enough to pick them up off of the bottom when the tank is full. At 70ft that wetsuit should still be about 20lbs positive, so you have 55lbs of ballast on between a full tank, the rig, and lead, less 20lbs of lift from the suit instead of 40, and you don't have the weight of your head, so you're at 35lbs of negative ballast at depth. That is where you need a 40lb wing.

Now, this is obviously the worst case scenario, drysuits are highly recommended at that level because the lack of buoyancy change with regards to depth is very useful for neutral buoyancy scenarios, and a cave filled LP104 isn't all that common of a single tank, though a Worthington 130 is, and those are 12lbs negative when full. Many people will use two different singles wings if they do warm water stuff and cold water stuff in single tanks, but typically if you're diving in cold water, you go to doubles and a drysuit so you aren't carrying lead around.

Same scenario above but in a drysuit. Rig is 30lbs negative, drysuit is 35lbs positive *made up number*, need 20lbs of lead for balance purposes. Get to the bottom, and you have 50lbs of ballast, against 35lbs of buoyancy when full, so you can get away with a smaller 30lb wing *still have to factor head at the surface*.

When you are carrying things up from the bottom you should always use lift bags if they are more than about 5lbs, anything more and it can cause serious problems for you on ascent and is dangerous. Lift bags are relatively cheap and you generally aren't picking things up from the bottom. This is why you inflate an unconscious divers bc to get them neutral for retrieval instead of your own. Not safe otherwise.

Hi there, you seem to know a fair amount about lift capacity, which completely boggles me! I'm looking to buy a wing but not sure the lift capacity I need. I dive mainly in warm water with 3mm or 5mm suit carrying 10Ibs & 18Ibs respectively and using AL80s. I also like to be positively bouyant when on the surface as I sometimes have to deal with surface diver problems. I am currently looking at Hollis's S25LX or the S38LX. Would the former be to little & the latter too much? Thx

 

[Vegan Shark]

Hi there, you seem to know a fair amount about lift capacity, which completely boggles me! I'm looking to buy a wing but not sure the lift capacity I need. I dive mainly in warm water with 3mm or 5mm suit carrying 10Ibs & 18Ibs respectively and using AL80s. I also like to be positively bouyant when on the surface as I sometimes have to deal with surface diver problems. I am currently looking at Hollis's S25LX or the S38LX. Would the former be to little & the latter too much? Thx

The S25 is more than enough with an AL80 in a 5mm suit. The 38 has enough lift for my steel double 100s, so using it with a single 80 would be overkill.

 

[danvolker]

Hi there, you seem to know a fair amount about lift capacity, which completely boggles me! I'm looking to buy a wing but not sure the lift capacity I need. I dive mainly in warm water with 3mm or 5mm suit carrying 10Ibs & 18Ibs respectively and using AL80s. I also like to be positively bouyant when on the surface as I sometimes have to deal with surface diver problems. I am currently looking at Hollis's S25LX or the S38LX. Would the former be to little & the latter too much? Thx

Personally, it would irk me to be forced to drag some huge wing BC in order to be able to deal with surface flotation issues of other divers...I like to be as close to zero drag in the underwater part of my dives as I can be.....My solution would be to use my 18 pound Halcyon Wing--which I currently use with everything from al 80 cu ft tanks, to hp120's....AND I would tow one of these torpedo floats, which are essentially a near zero drag lifeboat on the surfase--for any of these surface incidents to easily be dealt with....

OMER USA - Freediving and Spearfishing Equipment - Products

Of course, I dive Palm beach where Drift diving means we need to tow a low drag float behind each group of divers anyway....with the dive boat following the float...
Even with anchor diving, for the issue you point to as a concern, this would offer you the best of both worlds....a diver in your charge that is concerned as they approach the surface, would already be told to have headed up YOUR line to the torpedo....the torpedo has like 200 pounds or more of lift, and the one I have has handles on it, making it very easy for a diver to rest on, if they need to.....
And....if the diver hanging on to your torpedo needs you to.....you can tow them back to the boat much more easily with them hanging on to the torpedo, than would be possible with them holding on to you, and interfering with your kicking/propulsion.
While doing an hour long dive with your group, you can have a reel at your end of the line, clipped to a 6 pound weight....you can have the weight suspended off the bottom--held up by the torpedo as you tow it, and on reaching a place your group wants to stay at for a few minutes or longer, you can let out some line, and the weight settles on the bottom like an anchor....the plus for this, for you, is that if you suddenly had to deal with a diver problem at the surface, you could just pull the line up and grab the reel...if you used a hook with the reel like we do, the hook might need to be un-hooked from the bottom, which might be a problem if you have a diver on the surface you have to babysit on the float.



The drag on these is so low, that you can toss one of these out the back of a boat going 20 mph....and get a very small pull on the line....Try the same with one of those stupid round, red dive balls, and you will likely get pulled right off the back of the boat

We began using these in the early 90's on drift dives over deep reefs and wrecks at 220 to 300 feet deep, where the currents were so powerful that traditional floats were becoming almost impossible for the divers to tow where they wanted to go to---we were being pulled by the current like leaves in the wind....Even with scooters pulling the red balls....when we changed to the torpedos with thin but strong cave line or similar, the drag/pull became negligible.

 

[g1138]

Hi there, you seem to know a fair amount about lift capacity, which completely boggles me! I'm looking to buy a wing but not sure the lift capacity I need. I dive mainly in warm water with 3mm or 5mm suit carrying 10Ibs & 18Ibs respectively and using AL80s. I also like to be positively bouyant when on the surface as I sometimes have to deal with surface diver problems. I am currently looking at Hollis's S25LX or the S38LX. Would the former be to little & the latter too much? Thx

This comes with Rescue Diver Training. You don't use your own BC to help float a panicked diver. This creates a trim imbalance. You essentially have a very bouyant object on your back (the wing) and a very negative object on your front (the panic diver), you're going to end up struggling and rolling, dunking both your faces.

There are better techniques, like telling the diver to focus on you and drop their weights, orally inflate their BC.
OR you can get behind them and drop their weights for them. There's a technique to getting behind a panicked diver without being climbed on top of too.

You'll be fine with the S25. If you go with some HP tanks like an HP 120 you'll be taking weight off your belt to compensate and still be good.

 

[tbone1004]

s25 will be fine though I have a personal distaste for Hollis as a company so would recommend another brand. 25lbs is fine though, if you go to a steel tank, you'll drop 4-5 of those lbs which will be taken back up by the extra weight of the air. 18lbs is cutting it too close with 18lbs on your belt. The wing will be seriously taxed at depth, not that it couldn't handle it, but while the wing is rated at 18lbs, the tank puts pressure on it and they never quite hold their true capacity in normal usage.

If you're spending Hollis money, I would recommend going to either Dive Rite, or Deep Sea Supply instead.
https://www.divegearexpress.com/bcs/pkg_metal.shtml
Hell if you need any other gear, these guys ship international free over $500USD, and for $310 you can get a wing with cam bands and a plate/harness, hard to argue there, would recommend adding the DGX Single Tank Adapter for $25
https://www.divegearexpress.com/bcs/backplates.shtml#1732
A lot of people don't like them, but I absolutely love them, and you get the added perk of 2 extra lbs to take off of the weight belt.
DRIS Dive Gear 28lb BP/W System | Dive Right In Scuba - Plainfield, IL - Dive Right in Scuba
This is another good deal and comes with an STA for $380, different wing shape and a little more lift so if you are head heavy it helps a bit. You can get the wing alone for $200.

 

[danvolker]

I think the Halcyon 28 pound lift wing is the ideal solution ...I mention my use of the 18, mostly to illustrate that you can do well, without a high lift wing. My wife Sandra uses the 30 pound wing, whether in 3 mil suit, 5 mil, 7/8 or in her Drysuit.
For the 7/7 or Drysuit, she uses the 6 pound weighted STA, so that she can keep her perfectly balanced rig trimmed out with the increase in weight needed with these higher bouyancy suits....the weightbelt with more weight, would start to make her feet heavier, while the STA keeps her flat. ( she has both the non-weighted STA, and the weighted one)

 

[scubadiver888]

Hey stuartv,

You as a complete package (gear, wetsuit, tank, etc.) need to be neutral or negative. If you are positively buoyant then you will not be able to stay down. If you are too negatively buoyant then you will need to add air to your BC to compensate. The larger BC will add drag and cause you to use more air when diving. So you want to be as close to neutrally buoyant as possible as this will help to reduce the size of the BC.

You do need to start off negatively buoyant. If your tank contains 5 pounds of air, by the end of the dive you will only have 1 pound of air left. So you will be 4 pounds lighter but your volume displacement will be the same (the tank does not compress). So you will be 4 pounds more buoyant. Thus you need to carry extra weight to compensate for the air you will breath away. If you wanted to be extra careful you would add an extra 5 pounds of weight. This way if you run out of air (heaven forbid) you will not rocket to the surface. If you plan well the odds of this happening are low but some people will carry the extra weight, just in case.

This is how you determine how much extra weight you need. All the theory in the world is just theory. You will have to get in the water and see exactly how much weight it takes to sink. If you find you need 2 pounds of weight to sink with a full tank and the tank holds 5.7 pounds of air then you might want to wear 8 pounds of weight just to be safe.

So why do you need a wing with say 30 pounds of lift? One reason is where you place the weight. If I am 18 pounds positively buoyant (wetsuit) and my gear is 16 pounds negative buoyant then I might need 16 pounds of lift to float my wing when I'm not in it (putting your gear on at the surface in the water). However, if the extra 8 pounds I'm adding gets added to the rig (ditchable weights) then the rig is actually 24 pounds negative at the start of the dive. So maybe I need a wing with 25 pounds of lift. On the other hand, if I wear the extra 8 pounds on a weight belt I won't need the extra lift in the wing.

Another example might be drysuit diving or cold water diving. I might be 20 pounds positively buoyant in a 7mm wetsuit with a 7mm vest, gloves, hood, etc. So now I need 18 pounds to sink with a full tank or 24 pounds with an empty tank. Rather then wearing 24 pounds of lead on a belt I might switch from a 2 pound plate to a 10 pound plate. I might switch from an AL80 to steel tank (6 pounds more negative). So now my gear is 14 pounds heavier. I cannot take the weight off the rig and wear it because it is in the plate and the tank. So I need a wing with 14 pounds more lift. So now a wing with 38 pounds of lift is required to float my rig without me in it.

Bottom line, it isn't about the lift needed to get you to the surface. I usually like to be in good enough shape that I can swim my gear to the surface even if it is 6 pounds negative. The lift, for me, is about floating my gear on the surface at the start of the dive. That seems to be when I need the most lift.

Additionally, if you want to lift things from the bottom you want to use a lift bag. Using your wing to lift things from the bottom is a bad idea. For example, you are lifting something from the bottom using your wing. It breaks away and drops to the bottom. Your wing is over-inflated. You are sent rocketing to the surface. You are now at risk for AGE or DCS. On the other hand, if you are using a lift bag to lift things from the bottom, the item breaks away and drops to the bottom. The lift bag rockets to the surface. So long as you are not attached to the lift bag. You stay neutral and watch the bag rocket away. You slowly go to the surface and retrieve your lift bag.

There are plenty of threads on here about purchasing a BP/W system. You might want to search for "new BP/W" or "recommend BP/W" and see what you find.

 

[Manta Man]

The S25 is more than enough with an AL80 in a 5mm suit. The 38 has enough lift for my steel double 100s, so using it with a single 80 would be overkill.

Thx for the reply. I had, still have, my doubts regarding the S25. I mean, and I am more than likely all wrong about this but..., If I calculate my total downward force on a 30m dive I get - Reg:2Ibs + SS Plate & STA 9Ibs + Weights 7Ibs + Harnes & D-rings etc:2Ibs + Other variable:1Ibs + Compressed suit -9Ibs = 31Ibs. So, in theory I would have, I think - big question mark here, 31Ibs of negative buoyancy?????

So, how would a 25Ibs wing be able to keep me off the bottom?

Help!!!