How heavy should my back plate be?

[trip17]

Would it be better then to use an Al bp then just add weights?

 

[LeadTurn_SD]

Would it be better then to use an Al bp then just add weights?

Read post #11 by Tobin again.

It sounds to me like you may be overweighted (a bit) if you use a stainless steel plate, assuming you are correctly weighted with 4-5 lbs with a 3mm wetsuit and jacket BC. You could use a stainless plate, but it is possible you would have little or no ditchable weight.

I'm a big fan of ditchable weight whenever possible. But as stated above, with lean divers in tropical waters and thin exposure suits, sometimes no additional weight is needed (beyond the rig). But if you have the option of configuring your rig so you can ditch weight in an emergency (typically on the surface), then that is what I prefer for safety reasons.

FYI: I live in Hawaii, dive in a 3mm full, use a stainless backplate and typically have 6-8 lbs or ditchable weight on a belt.... but I suspect I have a bit more, ummm, bioprene than you do, so I'm a bit of a "floater"

Best wishes.

 

[trip17]

I normally dive in warm / tropical water and use a 3mm suit.

 

[LeadTurn_SD]

I normally dive in warm / tropical water and use a 3mm suit.

Then, if you are using 4-5 lbs of ballast with the 3mm, I'd say aluminum plate.

The aluminum plate weighs about 2 lbs, plus the 2-3 lbs of inherant positive buoyancy "lost" by switching from a standard BC to a BP/W... you'll be pretty near to your current weighting, and may not need any additional ballast weight.

Best wishes.

 

[klauricella]

I also agree with rstofer. What you need to remember is at depth your wetsuit crushes and is not as buoyant as it is at the surface. When you get rid of all your ditchable weight make sure with no air you can swim up from depth. I use a alum backplate and alum tank. This way at the end of dive or out off air you tank will give you extra lift, where steel does not change as much.

Kevin

 

[trip17]

Thanks for all your suggestions. I really appreciate it

 

[eelnoraa]

I only only had about 10 dive with SS plate, I use rental AL80. But I start to think that if I were to use steel tank, I maybe better off with AL plate.

Currently, with SS plate, AL80, 7mm(old rental semi dry), I put 4 lb on upper cam band and 12lb on belt. Steel 120 is about -8lb compare to AL80. So I will lose the 4lb on cam band, and 4lb on belt. I will only need to carry 8lb on myself. If I were to lose my rig, I think I will shoot up to surface. Should I try to weight myself without the rig to as close to neutural as possble?

 

[LeadTurn_SD]

I only only had about 10 dive with SS plate, I use rental AL80. But I start to think that if I were to use steel tank, I maybe better off with AL plate.

Currently, with SS plate, AL80, 7mm(old rental semi dry), I put 4 lb on upper cam band and 12lb on belt. Steel 120 is about -8lb compare to AL80. So I will lose the 4lb on cam band, and 4lb on belt. I will only need to carry 8lb on myself. If I were to lose my rig, I think I will shoot up to surface. Should I try to weight myself without the rig to as close to neutural as possble?

Good question. But neutral weighting at what depth? At the surface, 15 feet, 30, 60? You don't want to add more total ballast than you actually need with your rig on....

It can be a good thing to determine how much buoyancy your wetsuit provides on the surface, so you can see how much it could lose (in theory) at depth. It is also good to know if you can swim the rig up from depth with an empty wing and without dropping ballast weights. And to know if you can keep your head above water for a few minutes on the surface with an empty wing without dropping ballast weights.

If you are properly weighted, you should be somewhere between "neutral" to maybe 5-6 pounds negative on the surface at the start of the dive.

If you are properly weighted and can still carry 8 lbs on your belt, ditching the belt should allow you to easily tread water on the surface in the event of a wing failure (because after dropping the belt you'll be slightly positive), provide (probably) enough weight to keep you from shooting up like a cork from depth if you need to remove your rig to clear an entanglement (because you'll be neutral to slightly negative), and should be enough ditchable weight at depth to handle a wing failure.

But all this depends on proper weighting and having enough ditchable weight to compensate for the buoyancy lost by your wetsuit at depth, and the amount of "fixed" weight on your rig.

Best wishes.

 

[Eric Sedletzky]

Hey all! I'm currently using a scuba pro knighthawk BCD + 4-5lbs of weights (total). I'm thinking of switching to a back plate system however, I'm unsure if I should get a 4lbs stainless steel back plate or an aluminum one.

Ideally, I don't want to add weights anymore.


Thanks in advance

I make stainless steel plate called the Freedom Plate that's 4lbs. 2oz,
with an alternate configuration of making it 3lbs. 2oz.The alternate would be to remove the rail that comes with it and use just the plate. The rail is a tank bracket that places the tank in a certail position allowing the plate to follow the contours of your lower back, but the plate can be used without it for extremely close tank to body fit.

It's a plate specifically designed for single tank use.
You can see it here:
http://www.scubaboard.com/forums/bu...t-systems/301048-new-freedom-plates-here.html
Scroll down through the thread and I have more pics throughout the thread.
If single tank diving is primarily what you plan to do this might work for you.


I don't have a website yet but I'm working on it.

Eric