Doubles and Wing lift needed

[SCUBA482]

Planning my switch to BP/W to run doubles and enter the tech world. I dive mostly So Cal cooler waters with either wetsuit or drysuit. I'm 6-2 and weigh about 230lbs. I am planning on taking 2 of my HP100s and making a double set and possibly slinging a AL40 in the future. Main questions are SS or Al backplate and then ~ lift capacity needed in the wing? GUE website suggests no more than 65 lbs of lift needed PERIOD, but is that for Al or steel tanks? So far my guess is SS backplate, 60lb lift wing and then adjust weight as needed.

Any input / experiences in helping me determine some starting points to research would be greatly appreciated.

Thanks in advance.

 

[TSandM]

Well, a wing has to do two things . . . float your rig at the surface, and compensate for lost buoyancy at depth.

HP100s, as long as you aren't using the ultra-negative Fabers, are no more than 10 lbs negative full. Add 5 lbs or so for bands and manifold, and no more than a few more pounds for regs and metal bits of harness, and you're still under 30 lbs negative. Add a steel BP, still 35. A 40 lb wing should float that setup. If you need a big v-weight to sink, you might be pushing the flotation on a 40 lb wing, and need to go up.

I can't imagine you needing to use an aluminum BP in SoCal's cold water. Even with a steel plate and HP100s, at your height, I'd imagine you would probably need some additional ballast, which can be a v-weight, tail weight or weight belt, depending on where you want to carry weight and where you need it to balance the head-heavy nature of the tanks.

I use a 40 lb wing with HP100s and one deco bottle in Puget Sound.

 

[cool_hardware52]

Planning my switch to BP/W to run doubles and enter the tech world. I dive mostly So Cal cooler waters with either wetsuit or drysuit. I'm 6-2 and weigh about 230lbs. I am planning on taking 2 of my HP100s and making a double set and possibly slinging a AL40 in the future. Main questions are SS or Al backplate and then ~ lift capacity needed in the wing? GUE website suggests no more than 65 lbs of lift needed PERIOD, but is that for Al or steel tanks? So far my guess is SS backplate, 60lb lift wing and then adjust weight as needed.

Any input / experiences in helping me determine some starting points to research would be greatly appreciated.

Thanks in advance.

To expand just a bit.

The basic math for minimum wing capacity is:

The buoyancy of your exposure suit + the weight of your back gas + 2 or 3 lbs.

Your 2 x 100's will hold about 16 lbs of air or nitrox

16 +3 = 19 40 - 19 = 21 If your drysuit is 21 lbs or less buoyant with minimum gas in it a 40 is a reasonable choice.

I'd *guess* for a guy your size a shell suit with a medium weight undergarment is more than 21 lbs buoyant. In any event you should test your own suit.

We sell a lot of 49 lbs wing for use in the local environments here in SoCal.

You should also give some thought to the risks of steel doubles in the ocean in a wetsuit. Not something I would recommend.

Tobin

 

[SCUBA482]

Thanks for the info...I think I'm leaning to the Apeks WTX-6R, redundant bladder with 60lbs of lift since I do dive wet often and use steel tanks...

 

[Louis E]

An ALuminum Back plate with weights attached down it center is a good option. You can remove the weight for travel or if you have real negitive steel doubles.