Setting up a BP/W rig for the first time

[phlegm]

Hey there,

so I got myself a backplate and wing. Trianta 28lb kit from DRiS (continuous webbing harness). I also have two weight pockets which I have threaded onto the cambands (I threaded one camband backwards so I can have one weight on either side of the tank to hopefully help with trim). I also have a weight belt but I'm not really sure whether or not to use it. Plate, STA and cambands are all stainless steel, and weigh 4.3kg all up. I have been adding another 2.6kg or so in the two camband weights, which leaves me slightly positive, or adding another 1.5kg on a weightbelt which leaves me slightly too negative (I like to carry the lowest amount I can get away with). I'm about 6'2", 95kg and I wear a 7mm wetsuit.

I'm struggling to really get it fine tuned. I think this stems from being unsure where to position the straps. I currently have the shoulder straps done up really quite tight, which brings the plate high enough up my back that I can easily reach it over my shoulder. I had been told to leave them an inch or two loose, but I found that while diving the whole rig tends to ride up too high. I keep smacking my head on 1st stage so I need to get the tank lower, but I already have the cambands threaded to hold the tank as low as I can.

I had tightened the crotch strap a lot in an attempt to keep the rig from riding up, but I think I've overdone it. Where should the waist strap sit? Currently if I have the crotch strap tight then it drags the waist strap down a lot so it doesn't really sit nice and flat, but if I have it loose the waist strap sits really high up on me, in line with my belly button.

In the water I seem to have a tendency to be quite top heavy, which makes me wonder if the weight on the top camband is really a good idea. I'm in negative jetfins but they don't seem to really offset the top heaviness. Trim is all over the place anyway.

Any advice, resources or pictures would be highly appreciated. Please ask if any of this doesn't make sense.

Cheers!

 

[Oldbear]

I apologize that I did not include any examples but I have to leave real soon. You should try searching YouTube. I always seem to find something useful there. I also thin Dive Gear Exchange has videos that might be useful too.

Congrats on your BP and enjoy.

 

[TSandM]

Loosen the shoulder straps and tighten the crotch strap. With a single tank, you can let the plate sit a little lower on your back, and the crotch strap will keep the rig from riding up so high. This will help with your head-heavy issue, but moving the other weight pocket to the bottom cambands will help, too.

What kind of tank are you diving? If it's aluminum, they get very butt-light as they empty, so you may have to weight yourself feet-heavy to begin with, in order not to be too head heavy at the end.

Don't worry about the 1.5 kg. It really isn't necessary to parse your weighting that carefully.

 

[phlegm]

Hiring tanks from the uni dive club, so it varies week to week. sometimes steel, sometimes ally.

How tight is tight for the crotch strap though? how high up up your front should it sit?

---------- Post added February 13th, 2015 at 07:23 AM ----------

I'd put both weight pockets on the bottom camband but there physically isn't room to do so without obstructing the velcro

 

[Rand]

XS Scuba makes weight pockets with velcro on the flap so as not to lose real estate on your cam bands, if that helps with trimming you out.

I've used this link before for helping to fit a BP/W harness correctly.

 

[KevinNM]

iirc, I was told the crotch strap should extend a few fingers or an inch slack above the buckled waist belt.Ive seen this article referenced before, and it pretty much matches what my instructor had me do.
DIR-diver.com - Adjust the backplate

I originally had the shoulder straps too tight and some changes were needed. I ended up putting in triglides to prevent me from overtightening the straps.

I also ended up needing all my weight in my weight pockets on my belt, the tank cam band pouches just made me head heavy. That really surprised me. Everyone's body is different and you might need very different weight distribution from me, and you might also need to change your weight distribution if you change exposure suit or even just dry suit undergarments.

 

[TSandM]

I like the crotch strap tight enough to bow the waist strap downwards.

I did an hour and a half in the water with Bob Sherwood a number of years ago. Bob has a well-deserved reputation as the guru of trim -- of harness adjustments and weight placement to allow the diver to balance. I was truly AMAZED at how much he loosened my shoulder straps. It made the harness infinitely easier to get in and out of, and with snugging up the crotch strap, the rig remained very stable. And this was with DOUBLE tanks.