Bpw and weights

[rab1412000]

Hi everyone!
After years of diving jacket type bcds I've decided to get a padded oms backplate and harness, with a single tank adapter and a thirty pound wing. The backplate itself is not metal for portability /travel purposes.
I use six pound weights on my sea quest pro qd+ bcd. Most people recommend less weight for a bpw setup, owing to the weight of the plate I'm guessing.
Since my setup is not metal and more akin to a dive rite trans pack, what weight do you guys recommend I start with?
I know the best way to determine this is to take the gear out for a test dive, but I just wanted to get a starting point if there was some 'formula' for transitioning weight from jacket bcds to padded bpw's
Tia


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[buddhasummer]

A BCD will have inherent buoyancy, how much will depend on how much padding etc it has, maybe a couple of pounds or more. The weight reduction in the moving from a BCD to BP/W is a combination of weight of plate, STA if youre using one and the lead that was required to sink the BCD. Without trying to be a smart ass obviously a proper weight check is the way to go to be sure. The padding on the plate will of course add some buoyancy although not a great deal. If you're not using a metal plate you may find your weighting is similar, save a pound or two. But I'm just guessing, a weight check would be the way go and remove a little at a time. Good luck.

 

[PinkInkScuba]

I would start with the same 6lbs of weight as you have not really gained the advantage of the BP/W combination since there is no "plate" involved. An aluminum plate will usually allow you to drop 2-3lbs and stainless steel plate will allow you to drop 5-6lbs on average. So for the starting point on your new setup, without actually doing a buoyancy check would be to start with the same amount.

 

[Colliam7]

After years of diving jacket type bcds I've decided to get a padded oms backplate and harness, with a single tank adapter and a thirty pound wing. The backplate itself is not metal for portability /travel purposes.

Are you referring to a rigid 'plastic' backplate - such as a Kydex plate, or a 'soft' backplate like a TransPac? I am not familiar with an OMS non-metal, rigid backplate, so it is hard to say what the specific buoyancy difference might be. But, if you go with the padding that OMS offers on the Comfort Harness, and the backplate pad and optional cumberband, you probably won't find a lot of difference in buoyancy characteristics, so starting with the 6 lbs you dive now and working down is a good suggestion.

I just wanted to get a starting point if there was some 'formula' for transitioning weight from jacket bcds to padded bpw's

No established / acceted 'formula' that I know of. As several have suggested, different people have a different 'rule of thumb' for the transition. I have also used a SeaQuest Pro QD for many years, for pool work. I also use a SS BP for fresh water. I use 6 lbs in the pool with a 1mm suit and the SeaQuest, no weight with the SS plate in fresh water, with a thicker (3mm) wetsuit.

 

[rab1412000]

It is the oms iq pack, so I think it's similar to the transpack except that it does have a steel single tank adapter, which I think weighs two pounds.

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[buddhasummer]

That being the case, as has been suggested, start with normal weight and take out a pound at a time you're probably pretty close as is. Good luck, let us know how you get on. Cheers.

 

[rab1412000]

Thanks a lot guys. I scheduled a pool session tomorrow to test my new setup before a three day dive trip starting Sunday.
I'll take all of your tips and hope all goes well. Excited to try the new gear

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[TSandM]

The two reasons people can drop weight when switching to a backplate setup are the weight of the plate, and the lack of padding. You don't have weight from a plate, and you have added padding, so I agree with everyone who has said to stay with the weight you currently use, and then weight check to see if you can take any of it off. At worst, I wouldn't think you'd be any more than one or two pounds overweighted, and it shouldn't be difficult to cope with that.

 

[rab1412000]

i tested out my gear today in the pool. with 4 pounds of weight i am still slightly negatively bouyant at 250 psi at 15 feet. so i feel this is the right weight for me in a sea setting.
however ill play it conservative and stick to 6 pounds on my first (actual) dive and move on to 4 pounds on subsequent dives if i feel negatively bouyant at 20 feet/500 psi.

 

[TravisD]

The rough math for Fresh Water to Salt Water is to add 2.5% of your TOTAL weight (as if you, in full gear and weights, stood on a scale). So, if your total weight now was 250lbs, you're looking at needing an extra 6lbs in salt water. This is only theory of course, but don't be surprised when you need more than 2lbs!