Mares Pure Hybrid BCD vs Backplate - Will I really reduce weight by 8lbs?

[Zef]

Don't be too hung up on the weight/buoyancy issue....you will invariably be cutting some lead from your belt unless you go with a light weight aluminum plate with lots of padding...and even then you could probably lose some lead over a bcd. But in the end you will need to do either a proper weight check before or after you dive the new setup, or you will need to just go by trial and error until you establish the proper amount of weight you need and have it positioned where you need it for good body position (trim) in the water.

A proper weight check would be to take a tank with 50 bar or @500 PSI....or whatever pressure you would expect to have at your 5m/15ft safety stop and add/remove lead as needed until you have the proper amount. Here is a general guide for how to conduct the weight check:
1. Ensure harness is properly adjusted and crotch strap is not too loose.
2. Fill wing with enough air to comfortably float at surface.
3. Relax and just hang out at the surface until your breathing is calm and consistent.
4. Pay attention to your body and ensure you are not kicking or sculling...just relax and hang.
5. with a regulator in you mouth, take a normal size breath and hold it...don't overfill your lungs.
6. Start emptying the air from your wing.
7a. If you sink then add some air to your wing to regain the surface and remove some lead and try again.
7b. If you float then add some lead and try again.
8. You have the correct amount of lead if when holding a normal breath you are floating at eye level.

Realize that any change to your configuration can have an impact on how much lead you need to wear. For instance if you do a weight check with a steel cylinder and switch to a similar capacity aluminum cylinder you will most likely need to wear more lead as aluminum cylinders tend to be more buoyant than steel cylinders as they empty.

As important as how much ballast you need is where your ballast is situated. You should position any ballast added so that you can easily and comfortably establish and maintain a horizontal body position in the water.

-Z

 

[eelnoraa]

Most likely, you will not lose 8lb of weight (ballast), but you may lose 8lb of lead. Since SS backplate is generally about 5lb ( the claimed 6lb SS plate, mostly measured to 5lb or even under). That itself reduce your lead by 5lb. You have lose any weight yet, just shift from lead to plate. Then the inherent buoyancy of BC padding can be 2-3lb. That is the amount of weight you will reduce. But as seen from lead point of view, you remove ~8lb of lead. That is about it.

 

[Bob DBF]

Then the inherent buoyancy of BC padding can be 2-3lb. That is the amount of weight you will reduce. But as seen from lead point of view, you remove ~8lb of lead. That is about it.

Although my jacket was +5#, I switched ten years ago or so and the jacket was even older, so I dropped 5# and moved 5# of buoyancy. The big plus was getting that weight off the weight belt, and having a more stable load to carry because of the BP. The weight and stability of a rig is important when diving a 7mm farmer John in salt water off the NorCal coast. In addition it was way easier to attach trim weights effectively.



Bob