wing size, again...

[ripman3]

hey guys, I know this has been asked before....BUT, what size wing do I need? I read everyone talking about how your wing should float your rig. also, I read that for a single tank most people use 30 to 40 lb. wings. so I weighed my rig today and it is 85 lbs. I never hear about anyone using a wing of that size for single tanks. so what am I missing? just because I know you will all ask.
I will be in salt water.
I use a steel bp.
I use a 7 mm wet suit. one piece.
I have a 100 cf steel hp faber tank.
I use a 30 cf al pony bottle.
2 lights.
2 regs.
a bug bag.
a reel.
a strobe light.
85 lbs. so what size wing do I need?
thanks,

 

[tbone1004]

you need to weigh your rig in the water... If you're close to the water, buy a luggage scale and hang your rig from there and note the tank pressure and report that back.

Steel bp with misc stuff attached to it, 10lbs
Faber HP100- -1.5+ 113cf of gas =-11lbs
AL30-2lbs
pair of regulators, 4lbs
So we are at 28 ish lbs before we factor the suit in. I don't know how much buoyancy your suit has, but being a 7mm, it will be more than 2lbs, so I would go with a nominal 40lb wing for that setup. Deep Sea Supply LCD40 would be my first recommendation, Torus 35 would be the second, but having the extra few pounds isn't going to be an issue and your tanks are long enough to handle the LCD40 which is a fairly long wing. The key here is that you are using a long and skinny tank but still need a lot of weight, so your wing should match that. Most 40lb wings are quite wide, but the LCD40 is fairly narrow for as big of a wing as it is.

 

[ripman3]

thanks tbone. that's what I was missing, weighing the rig in water. I have a hog 32 lb. wing now. will that be ok with this setup? or will it not be enough lift?

 

[tbone1004]

I would not consider it sufficient lift. Will it work? probably, but it won't have a whole lot of extra lift if you need it for picking up anything from the bottom, or in an emergency keeping your head high and dry. What I am unsure of is how Hog measured their wing lift. One of the issues with many wing MFG's is they measure the unrestricted volume of their wings and that can result in a wing with less capacity than you think it might have. Only way to verify this is to set the rig up and put it on a scale. Fill the wing with water until it is full.

If it has a full 32lbs of lift, then it will hold 32lbs of water

 

[ripman3]

thanks again tbone.

 

[NAM001]

if you are (swagging) -28 and you put on a suit the -28 will reduce to say -10 to -20. that gives you some reserve for aiding your buddy up in a failure with his. You can do it many ways. a previous estimation of -28 had no suit involved. so the 32 wing can handle it, worst configuration situation. you put on a suit and you NEED less but you have it. when you wear a suit and it suffers from compression then you will NEED the reserve, now the more you breath down the tank the more reserve you will regain for an emergency. I use 28-32 wings with a steel BP and a 3/2 shorty. no air in the wing at 6M and am neutral. The shorty is about 9# lift. I sometimes struggle staying on the surface with no wet suit on and diving the lp120 with a cave fill. For those dives I have a 40# wing. Although I don't dive with out a suit I do dive at times with a lavacore (No buoyancy). no I have an AL BPW with 40# for that. It is not the ideal confiruration but I use it in local lakes that are shallow. (less than 50') with a definite hard bottom. That way I don't have to change the BPW drastically.

 

[NAM001]

I would not consider it sufficient lift. Will it work? probably, but it won't have a whole lot of extra lift if you need it for picking up anything from the bottom, or in an emergency keeping your head high and dry. What I am unsure of is how Hog measured their wing lift. One of the issues with many wing MFG's is they measure the unrestricted volume of their wings and that can result in a wing with less capacity than you think it might have. Only way to verify this is to set the rig up and put it on a scale. Fill the wing with water until it is full.

If it has a full 32lbs of lift, then it will hold 32lbs of water

I agree fully. narrow wings using an 8" tank can drastically reduce the filled volumn of the wing a 32 could only fill to 25 because of tank mounting squeeze. especially if your wing is one that requires no STA. Like oxycheq or DSS and some others. If tobin was here he could add a bit to this discussion.

 

[ripman3]

im still snowed in so maybe I will test the wing tomorrow to see what kind of lift it really does have.

 

[tbone1004]

KWS, you missed something... You have to take the total negative buoyancy and add the buoyancy of a wetsuit, not subtract. If you subtract it you aren't accounting for wetsuit compression and that is really bad since a 7mm will lose a considerable amount of buoyancy at depth. It may not be the full positive buoyancy at the surface, but it will certainly be most of it. Surprised your 3/2 is that positive, what size is it? My xxl 5mm is less buoyant than that.

FWIW Tobin measures his wings on long 8" diameter tanks using the water capacity method above, while the rig is on. This applies to both singles and doubles. This ensures that any compression caused by the tank and your butt is accounted for and you get the real value, that's why some of his wings have strange lift numbers.

 

[NAM001]

KWS, you missed something... You have to take the total negative buoyancy and add the buoyancy of a wetsuit, not subtract. If you subtract it you aren't accounting for wetsuit compression and that is really bad since a 7mm will lose a considerable amount of buoyancy at depth. It may not be the full positive buoyancy at the surface, but it will certainly be most of it. Surprised your 3/2 is that positive, what size is it? My xxl 5mm is less buoyant than that.

FWIW Tobin measures his wings on long 8" diameter tanks using the water capacity method above, while the rig is on. This applies to both singles and doubles. This ensures that any compression caused by the tank and your butt is accounted for and you get the real value, that's why some of his wings have strange lift numbers.

If you subtract the lift fromt he wet suit you are the heaviest you will ever be and if the wing will lift that it will lift you with a wet suit on. A diffferent way of looking at it i supposed. wearing no wet suit is heavier than any wet suit once compressed. I think that i was speeking from the point of his neg buoyancy with the suit on . so subtracting it would be akin to having a compressed suit. I probably did not word that very well. Thanks for the catch.

Yes tobin does rate the wings for 8 inch tanks Other manufacturers that have very slim wings do not get the rated lift with a 8 inch tank. I have a 40# wing but i dont get that much lift with my lp95 or 120 mounted.