Help before I take the plunge on BP/W rig

[cool_hardware52]

If you weight yourself to "just" sink when you have a full tank then as you empty that tank it becomes lighter. I am not sure what tanks you are diving but you are likely seeing at least 5#+ swing in buoyancy. If you were "perfectly" weighted with a full tank then you will be 5# too light with at the end of the dive.

Breathing down a tank will make it lighter, 100 cuft of air or nitrox is about 8 lbs. That leaves about 5 lbs of "useable" in an al 80. OTOH exposure suits compress and loose a significant amount of buoyancy in the first 33 ft, where the ambient pressure is doubling from 1 ata to 2 ata. With a heavy exposure it's quite possible that your exposure suit could loose 5 lbs or more from the surface to 15 ft.

I like to weight new BP&W divers, who are using 5mm or thicker wetsuits and 80-100 cuft cylinders, so they are eyelevel at the surface with no gas in their wing and a full tank. This has proven to be pretty close to the example you provide below, i.e. neutral at their shallow stop with 500 psi and no gas in their wing.

The advantage to "eyelevel with a full tank and no gas in the wing" is that the diver can do it at the start of the dive, at the surface where access to more or less lead is easy.

They should of course confirm it with the method you suggest below.

The proper and only way to get your weight exactly right is to:
1. Put your full set-up on.
2. Get your tank to 500 psi or a little less.
3. Get to about 10 feet.
4. Start dropping weight until you can no longer stay there without movement.

I am not saying that you don't need 25# but I will say that it is a lot of weight and I would be very suprised if you couldn't drop at least several pounds.

It is quite typical for the new BP&W diver to "drop" more than the ~6 lbs that the backplate and harness represents.

I see a couple reasons for this:

Most jacket BC's are inherently buoyant, often from 2-4 lbs due to pads etc. Eliminating these "floaties" reduces he ballast required.

A well designed BP&W will allow the diver to fully vent his wing. Not having trapped gas in the BC reduces the weight the diver needs to hold a shallow stop

Many new BP&W divers are for the first time rigorously examining how much ballast they really need instead of a "rule of thumb" approach.

These frequently combine with a net reduction in "belt" of 10 lbs or more.

Good luck,

Tobin

 

[PerroneFord]

But I still see a lot of people who modify their Hog harness to attach a quick release buckle on a shoulder... they wouldn't if they were so happy.

Define "a lot of people". In the three years since I've bought my BP/W and have been closely observing other divers with them, I have seen exactly 1 who had a quick release of any kind on a hog rig.

Do you mean actually "glue" a pocket to a wet/dry suit???? Or is it just a manner of speaking? The ones I'm considering have an elastic wrap around the thigh and attach to the harness webbing, which seems fair enough.

Yes I do mean glue. As in with Aquasea,l which is a common method for attaching a pocket if one doesn't want to sew it there. The elastic wrap will frustrate you in short order as it slips, moves, falls down, etc. What seems tight on your leg at the surface, will get loose when you descend and the neoprene compresses, and the pocket will move.


But by all means, try it your way. Let us know how it all works out for you after a few months.

 

[cmburch]

I have a similar Rig, but for cold water. I purchased on sale from LeisurePro and SCUBAToys. Just under $700.
Dive Rite TransPlate, SS BP, STA, Lumbar Pad, SS tank cam straps, 2" Crotch Strap
OMS small pockets
Oxycheq Mach V Extreme 40lb

Hammerhead has a SS BP that requires some finishing work, but is less expensive.
The STA may not be needed and can be purchased later.
The extra weight can be purchased later.

My Rig is set-up so I can remove it and freedive without having to remove weight from my belt. I need the left shoulder release for easy removal (kayaking). And I got the STA for extra weight and also stability so it doesn't shift causing me to work harder to keep my balance when hiking down cliffs.