Wing sizing with double HP 100's. (+)

[kidsdream]

I know this has been asked many times, but I want to confirm my thoughts that a 42-45lb wing would be suitable for use with double HP100's (max 2 x 8.5/10lbs negative full).

While I will be doing most of my doubles diving dry (fresh water), I might on occasionally use this in the the ocean with just wet suit.

Thanks in advance.

 

[cool_hardware52]

I know this has been asked many times, but I want to confirm my thoughts that a 42-45lb wing would be suitable for use with double HP100's (max 2 x 8.5/10lbs negative full).

While I will be doing most of my doubles diving dry (fresh water), I might on occasionally use this in the the ocean with just wet suit.

Thanks in advance.

You need enough lift to be able to float your rig at the surface without you in it, and to be able to compensate for the max change in buoyancy of your exposure suit.

Your rig will be about -38 with full bottles. (Full tanks are about -20, bands and manifold are about -5, dual regs are ~-5, SS plate and harness will be about -6, and a can light will be about -2)

You will want to start the dive negative by at least the weight of your back gas, ~16 lbs. This means you will have to use at least 16 lbs of the capacity of your wing just to stay at the surface at the start of the dive.

If you were to suffer a total failure of your drysuit, you could in theory loose all the buoyancy of the suit, unlikely, but you could not loose more.

If we assume you are +25 lbs in your suit with minimum gas in the suit then you would need 16 (weight of your gas) + 25 = 41 lbs.

Your rig provides about 22 lbs of ballast with empty bottles. If your suit is really +25 you will need a couple more lbs of ballast.

If your suit is no more than about +25 a 42 lbs wing would be the minimum I'd recommend. I'd suggest you determine how buoyant you are in just your undies and suit with minimum gas.


Tobin

 

[timle]

Again Tobin is a wealth of information.

I will simply add this my wife dives doubles HP 100s and with a stainless steel plate a 50lbs wing was JUST enough - with an aluminum plate 50lbs seems perfect. This is for fresh water.

In the ocean with just a wet suit - I'd ask myself, regardless of wing size, can I safely get to the surface with a total wing failure?

 

[kidsdream]

For reference I use about 14lbs of weight with a single steel 95 and SS BP with 6lb STA and was a bit overweighted even at the end of dive. So your calculations seem pretty accurate.

Looks like something around 50lbs lift would put me on the safe side.

Thanks

You need enough lift to be able to float your rig at the surface without you in it, and to be able to compensate for the max change in buoyancy of your exposure suit.

Your rig will be about -38 with full bottles. (Full tanks are about -20, bands and manifold are about -5, dual regs are ~-5, SS plate and harness will be about -6, and a can light will be about -2)

You will want to start the dive negative by at least the weight of your back gas, ~16 lbs. This means you will have to use at least 16 lbs of the capacity of your wing just to stay at the surface at the start of the dive.

If you were to suffer a total failure of your drysuit, you could in theory loose all the buoyancy of the suit, unlikely, but you could not loose more.

If we assume you are +25 lbs in your suit with minimum gas in the suit then you would need 16 (weight of your gas) + 25 = 41 lbs.

Your rig provides about 22 lbs of ballast with empty bottles. If your suit is really +25 you will need a couple more lbs of ballast.

If your suit is no more than about +25 a 42 lbs wing would be the minimum I'd recommend. I'd suggest you determine how buoyant you are in just your undies and suit with minimum gas.


Tobin

 

[limeyx]

Again Tobin is a wealth of information.

I will simply add this my wife dives doubles HP 100s and with a stainless steel plate a 50lbs wing was JUST enough - with an aluminum plate 50lbs seems perfect. This is for fresh water.

In the ocean with just a wet suit - I'd ask myself, regardless of wing size, can I safely get to the surface with a total wing failure?

a 40-pounder works just fine for me with HP-100's, and up to 2 stage bottles (one AL40 and one 80) although with 2 full stages it might be a bit marginal (I would usually go to the 55 pounder for that)

This is with 200G thinsulate or 400G thinsulate in salt or fresh water.