Wing lift capacity calculations?

[jgoodstein]

I am trying to determine the lift capacity for a wing. My instructor whom I trust suggested i go with 40lbs of lift in whatever wing i end up with.. but really wants me diving halcyon (a story for another day). So I'm trying to figure out if there is an equation to determine optimal lift capacity and streamline for diving:

I am 6'3" 250lbs. I am almost neutrally buoyant (skin diving i only wear 2lbs). If i wear a jacket BC i wear no more then 5lbs and with BPW I usually wear 2-4lbs. If i wear a 3mm shorty I add 2-3 lbs. I dive with an 80 AL tank. I will be diving with a Dive Rite Steel backplate and harness. I'm not really a fan of the DR wings and looking at some others. . My issue is how did my instructor come up with the 40lb lift capacity for the wing. Is there some sort of calculator? I called DSS, OMS, DR, and Halcyon and they all said ask my instructor (as not to take a liability claim), yet most agreed that 40 is enough to a little over enough for me when i pushed them.

Sure I could just settle for 40 is good enough... but why?

 

[herman]

40 lbs is way too much if you are diving 2-4 lbs of lead and single AL 80s. You only need enough lift to either A: keep your reg afloat at the surface with anything you might attach to it (like intergrated weights) or B: to compensate for wetsuit compression at depth. If you are not diving a heavy wet suit this one is not an issue.
So, how much go you need? Add up the negative buoyancy (not to be confused with the weight of the items- an AL-80 weights around 35 lbs but is only about 2-3 lbs negative full and 1-2 positive near empty) of everything you might carry and get the next larger wing. Based on what you have listed, a 15-20 lb wing will likely do nicely. Unless you are diving a huge wetsuit or large steel double tanks, there is no need for anything near a 40lb wing.

 

[pjones]

Are you planning on doing any or much cold water diving? What direction are you planing to go with the new hobby, Cave, wreck, or staying recreational?

Answer those and you will get a more accurate response from the more experienced on the board.

I dive cold water (drysuit) with a SS BP and some accessories, I have a 40 lb wing and appreciate what it does for me. If I were in warm water than I'm sure It would be over sized but can't imagine it would effect my dive excessively. I plan on traveling around with it and wanted a wing that would work well in my native waters and if nothing else get me by safely while I travel. My thought process says that its easier to dive with a slightly larger wing when traveling than it is to dive with a wing that is too small. I haven't the experience to offer much more than that though. You can take that for what its worth (about 2 cents)

 

[vinegarbiscuit]

Check this out: http://www.scubaboard.com/forums/bu...ems/158370-ultimate-wing-lift-calculator.html

Some wing manufactuers will work with you to determine the optimum wing for your needs (existing and future). Tobin of Deep Sea Supply is a perfect example. He'll ask about your current gear configuration (exposure protection, tanks, regulators, lights and so on) and ask if there's a possibility of changing your gear as your experience and and training broaden. He'll then give his recommendation on the optimum wing.

I concur that DR singles wings aren't the easiest to dive with. My Venture wing tacoed terribly, which made it difficult to vent (not without adopting some very weird positions, anyway). I think you're wise to consider the different brands out there - DSS, Hog, Oxycheq, Halcyon, and OMS to name a few. Good luck!

 

[jgoodstein]

I'm a warm water diver if the water is in the 60's I'm not going in. I live in South Florida and do mostly Caribbean diving 70'2 and 80's as far as water temp. Most is rec, some wall and eventually some wreck diving. no cave or cold on my personal time/equipment. the heaviest I go is a 3mm full suit with a 5/3 hooded vest for low 70's.

The reason I'm going with BPW is to be flexible. If i need an extra wing I will gladly purchase one for my personal needs. But for now I'm just trying to figure out how the calculations are made and which would be the best for me.