BPW Weighting: Overweight with no Lead

[Almanac]

Hello All,

I have recently changed my BCD from a Zeagle Stiletto to a DGX BPW with an aluminum plate. I completed a standard weight check (BCD empty, Full breath, 500psi, float at eye level) this weekend in a 3mm suit and a AL80 and was natural with 6lbs of lead. I usually dive with a Steel 100 and in the summer no wet suit. I am afraid that I will be significantly overweighed in this configuration. When not wearing a wet suit, is there any way that I can add buoyancy to my BPW or will I need to switch back to the Stiletto?

For reference:

• Height: 6ft
• Weight: 185lbs
• Tanks Available: Steel 100 and AL80
• Backplates Available: Steel and Aluminum
• Wet Suits Available: 3mm Full and 2/3mm Shorty

Current Weighting:

• Stiletto, AL80, No Wet Suit: 10lbs
• Stiletto, Steel 100, No Wet Suit: 4lbs
• Stiletto, Steel 100, 3mm Wet Suit: 12lbs
• AL BPW, AL80, 3mm Wet Suit: 6lbs
• AL BPW, AL80, No Wet Suit: -3lbs (Calculated)
• AL BPW, Steel 100, 3mm Wet Suit: 2lbs (Calculated)
• AL BPW, Steel 100, No Wet Suit: -8lbs (Calculated)

I might be overweighed in the Stiletto, but so far it has not been an issue. The obvious answer is to just dive the AL80, but I like the extra gas the Steel 100 provides. Any advice is welcome and appreciated.

 

[Nick_Radov]

One option would be to buy an AL100 tank. Those are positively buoyant. They're not very popular so you would probably have to special order it.

 

[scubadada]

Wear your wetsuit

Do a proper weight check at the end of your dive when using your BP&W when diving with no wet suit and an AL80 or a steel 100. Your weights when using the Zeagle BC seem high to me.

Actually, do a proper weight check with whatever system you are using. No gas in BC, reserve pressure in cylinder, neutrally buoyant at 15 feet for the safety stop and able to make a slow, controlled final ascent to the surface.

 

[Almanac]

One option would be to buy an AL100 tank. Those are positively buoyant. They're not very popular so you would probably have to special order it.

Thank you for the reply. Good idea, but I was hoping to not buy more tanks. Especially non standard ones.

Wear your wetsuit

Do a proper weight check at the end of your dive when using your BP&W when diving with no wet suit and an AL80 or a steel 100. Your weights when using the Zeagle BC seem high to me.

Also a good solution, but the water temperature in the summer here in Florida is kind of warm. I tend to overheat in a wet suit in anything above 82F. I might just have to suck it up. As for the Zeagle BC weight, that was what my instructor set me up with. After diving with some other people that where larger and using less weight I too thought it was higher than it should be. I was expecting a 6lbs swing not a 12lbs swing. I will wait for the water to get warmer before I recheck my weight without a wet suit.

 

[scubadada]

...Also a good solution, but the water temperature in the summer here in Florida is kind of warm. I tend to overheat in a wet suit in anything above 82F. I might just have to suck it up. As for the Zeagle BC weight, that was what my instructor set me up with. After diving with some other people that where larger and using less weight I too thought it was higher than it should be. I was expecting a 6lbs swing not a 12lbs swing. I will wait for the water to get warmer before I recheck my weight without a wet suit.

I think your weights are off. I edited my post somewhat including definition of proper weight check. Try it out, regardless of what you are diving.

 

[Nemrod]

Skip the steel 100 with a 6 pounds swing in summer with no rubber suit. Get a textile plate like the Oxy Ultralight. You can then configure the weight to include some weight that can be ditched to provide positive buoyancy even with a deflated wing on the surface.

 

[inquis]

Your calculated weight differences for wetsuit vs no suit are inconsistent: either 8, 9, or 10 lb. I also think those are all too high, having directly measured the surface buoyancy of an XL Bare Reactive 3mm at 7.6 lb (likely more than your 3mm has).

The real issue, however, is the weight check is more accurately done at safety stop depth, and wetsuit compression reduces the required weight change to about 5 lb of difference for the 3mm wetsuit in your size vs no suit.

Safety stop depth, empty wing, reserve pressure, you should just drift down at the end of a normal exhale.

 

[Brett Hatch]

Agree with the other posters that your reference weight in your other BCD is likely a little bit overweighted

Every body is different, but I'll give you my numbers as a point of reference, since we're about the same size. I'm 6 feet, 175 pounds, and when diving in saltwater in a T-shirt and shorts with an AL80 and stainless steel backplate, I don't need any lead. In a 3mm full suit I use 4 pounds of lead

Stainless backplates are about 4 pounds more negative than aluminum backplates, so I would expect to need 4 pounds if I switched to aluminum. And an HP100 tank is about 5 pounds more negative than an AL80, so I'd expect to shed about 5 pounds. Altogether, using an HP100 with an AL plate should be within a pound or so difference.

Cheers

 

[lowwall]

I don't see the problem. By your own calculations you will be neutral at then end of a dive with no lead using your plate and no wetsuit.

OK, you will be 6 pounds heavy at the beginning of the dive with no ditchable weight. But you still have a wing and a full tank of gas to deal with any problems. You should also be able to swim up 6 pounds without any difficulty. If you feel you need redundant buoyancy, carry a decent sized DSMB. You can also wear a 3mm shorty if you want some neoprene but don't want to worry about overheating. It's easy to let water in if you get hot.

 

[Almanac]

I think your weights are off. I edited my post somewhat including definition of proper weight check. Try it out, regardless of what you are diving.

I agree that my weights are off for the Zeagle. I was using them as reference fore the change. I am pretty confident in the BPW numbers, but they were done on the surface and not 10-15ft. I guess I will have to go diving again (Oh No ).

Skip the steel 100 with a 6 pounds swing in summer with no rubber suit. Get a textile plate like the Oxy Ultralight. You can then configure the weight to include some weight that can be ditched to provide positive buoyancy even with a deflated wing on the surface.

Interesting idea I will have to look into that.

Your calculated weight differences for wetsuit vs no suit are inconsistent: either 8, 9, or 10 lb. I also think those are all too high, having directly measured the surface buoyancy of an XL Bare Reactive 3mm at 7.6 lb (likely more than your 3mm has).

The real issue, however, is the weight check is more accurately done at safety stop depth, and wetsuit compression reduces the required weight change to about 5 lb of difference for the 3mm wetsuit in your size vs no suit.

Safety stop depth, empty wing, reserve pressure, you should just drift down at the end of a normal exhale.

The inconsistencies come from rounding to the closest even number to trim out. The suit is a Medium 3mm Bare Reactive that I have not measured individually. I probably assigned to much buoyancy to it in my calculation as I was going with 5% of body weight. I will try a weight check at safety stop depth next time I dive. I appreciate your input, especially the wetsuit buoyancy reference.