Cold Water Single Tank Kit Without Weight Belt

[RobPNW]

So I'm trying to put together my first cold water kit and wondering if I can get away with no weight belt, and if so, what size wing I will need. This is more of a feasibility question and if it's too difficult, I can always use a belt. I'm not concerned at all about warm water because of the buoyancy of AL tanks and significantly less exposure suit buoyancy.

My starting point is a Subgravity 6mm BP and a bar weight for the BP channel. I'm hoping to get HP100 steel tanks in the future. I have 2 S620ti 2nd stages, a MK17 Evo 1st stage and hoses for a long hose configuration. I wouldn't be carrying anything substantial like a powerful light.

I want to put my needed weight in trim pockets on one of the cam bands and the remainder in ditchable weight on my waist harness. Obviously, the goal is to be able to float the kit at the surface at the beginning of the dive with the steel tank full. I'm wondering if a 40 lb wing would cut it.

I know the BP weighs 10 lbs and the bar weight is 3 lbs but I don't know exactly how that translates to seawater negative buoyancy. I believe a full HP100 is around -8 lbs. If nearly all that translates to negative buoyancy, than that would be roughly -20 lbs and that's not even considering what more I would need to offset a drysuit.

Is there even a way to figure this out? Would I literally have to get in shallow water with everything but the wing and just add weight until I sink and then I would know the lift I need?

 

[Eric Sedletzky]

Why no weightbelt?? Do you just not like weightbelts or is there another reason?
All that ballast on your rig is going to be a hell of a lot of weight when you start factoring in a drysuit and thick undergarments. A 40# wing might not cut it. Do you plan on removing your rig on the surface regularly or would that only be for a rare emergency?
If not, then I would worry less about floating the rig on the surface and trying to get a wing to support that and just use a 40. If the 40 works to float your rig then it’s a bonus.

 

[RobPNW]

Why no weightbelt?? Do you just not like weightbelts or is there another reason?
All that ballast on your rig is going to be a hell of a lot of weight when you start factoring in a drysuit and thick undergarments. A 40# wing might not cut it. Do you plan on removing your rig on the surface regularly or would that only be for a rare emergency?
Of not, then I would worry less about floating the rig on the surface and trying to get a wing to support that.

Yeah Eric, I can wear a weight belt, just would prefer not to if I can get away with it. I may be SOL in this scenario.

 

[Robert H. Diver]

You shouldn’t need a weight belt…i only use 12-14 lbs plus my aluminum plate BPW when diving dry with an LP 85. I’m 6’2” and between 190-200lbs depending on time of year. (Your mileage may vary though). The weights go in my cam band trim pockets and the weight pockets on my waist strap. I don’t use ditch-able pouches.

 

[RobPNW]

You shouldn’t need a weight belt…i only use 12-14 lbs plus my aluminum plate BPW when diving dry with an LP 85. I’m 6’2” and between 190-200lbs depending on time of year. (Your mileage may vary though). The weights go in my cam band trim pockets and the weight pockets on my waist strap. I don’t use ditch-able pouches.

What lift wing do you have Robert and will it float your kit?

 

[FF / EMT]

So I'm trying to put together my first cold water kit and wondering if I can get away with no weight belt, and if so, what size wing I will need. This is more of a feasibility question and if it's too difficult, I can always use a belt. I'm not concerned at all about warm water because of the buoyancy of AL tanks and significantly less exposure suit buoyancy.

My starting point is a Subgravity 6mm BP and a bar weight for the BP channel. I'm hoping to get HP100 steel tanks in the future. I have 2 S620ti 2nd stages, a MK17 Evo 1st stage and hoses for a long hose configuration. I wouldn't be carrying anything substantial like a powerful light.

I want to put my needed weight in trim pockets on one of the cam bands and the remainder in ditchable weight on my waist harness. Obviously, the goal is to be able to float the kit at the surface at the beginning of the dive with the steel tank full. I'm wondering if a 40 lb wing would cut it.

I know the BP weighs 10 lbs and the bar weight is 3 lbs but I don't know exactly how that translates to seawater negative buoyancy. I believe a full HP100 is around -8 lbs. If nearly all that translates to negative buoyancy, than that would be roughly -20 lbs and that's not even considering what more I would need to offset a drysuit.

Is there even a way to figure this out? Would I literally have to get in shallow water with everything but the wing and just add weight until I sink and then I would know the lift I need?

Go jump in the water with you kit on, go swim around, get to about where you're going to get out of the water when you're at 350-500 psi, deflate everything, drysuit, bc, and you should be neutral, if you're not, you need weight, if you're sinking, you need less weight, but this will tell you how much weight you should have because this will be the lightest you'll be on a dive.

 

[Robert H. Diver]

What lift wing do you have Robert and will it float your kit?

I just have the DGX single tank 30lb wing. DGX Custom - DGX Gears Singles Harness / Backplate / Wing Package

Yes it has plenty of lift. The Drysuit does a lot of the work just by inflating to prevent squeeze, but if it failed the wing would have no problem.

 

[inquis]

Is there even a way to figure this out?

Fundamentally, you need to know the buoyancy of you+drysuit. Believe it or not that's it. All the ballast whether it's backplate steel, tank steel, lead, or even (negative ballast/positive buoyancy +4.4 lb) aluminum tank should add up to equal you+suit. Do that and you'll be neutral. Tack on the weight of the non-reserve air, and that's what the wing needs to support since you're not using a weightbelt.

One data point, I am 6'2", 215 lb, and +25 lb in my 45F layers fresh water. In salt water, buoyancy increases by 2.4% (average salinity), taking me to +30 lb. With 7 lb air I haven't breathed from an HP100 and a couple lbs of margin, I would need a 39 lb wing minimum. (In my 60F undergarments, the wing requirement drops to 30 lb.)

How cold are you planning to go? Do you have a known configuration from which to estimate suit buoyancy? Failing that, pile the lead on in a hot tub or pool. (Make sure the vent is in the normal setting and that you do, in fact, vent.)

 

[Zef]

When diving dry I use between 4 and 12kgs depending on the water temp/what undergarments I am wearing underneath.

I use a Dive Rite standard stainless steel back plate (@ 6lbs +/-), and my wing is Dive Rite Voyager XT (@ 35lbs lift).

I typically dive a 12L steel tank that weighs a bit over 2kg in the water when full.

I mostly find myself diving with between 4-6kgs of lead. With that amount of ballast, I will typically spread it between my Tecline trim pockets.

When diving with 8-10kgs, I will typically split the weight between the trim pockets and my Dive Rite QB weight pockets mounted on my harness waist strap.

I rarely dive with 12kg of lead.....when I do, I will put 2 to 4kg on a weight belt just because my total ballast along with tank, regulators, and torches would be getting pretty close to the limit of my wing....I have tested it and my wing will float it all, but I feel it is better with that much lead to move a bit to a belt. The reality though is that I almost never dive with this much lead even when diving water that is between 2c and 4c.

Hope that helps you a bit.

-Z

 

[RobPNW]

I like those trim pockets.