BP/W questions

I currently dive a back inflate Oceanic Excursion 2 BCD and although I am quite happy with it, I am also intersted in diving and becoming familiar with a BP/W set-up. My current tanks are steel LP 85's but I may be looking into going with HP 130's in the future.

I am looking to build this from the ground up rather then get one already preassembled.

I have several questions on things that I am just not clear on.

STA or not? Is the determining factor here if the plate has slots for the cam band(s)? Or, does it have more to do with pushing the tank out further from your back so you don't hit your head on the first stage?

Belt slides. Serrated or not?

I would be rigging the harness with a continuous piece of two inch webbing. Where the webbing comes down from the shoulder and goes out through the plate and back, do you use a belt slide on the back of the plate?

I was thinking I would also make the crotch strap as well but would either use a less rigid 2" webbing or go to one inch. Any recommendations on that?

On making the crotch strap, how do you form the front loop? Do you use a belt slide there or do you actually sew it closed?

How does it attach to the backplate? Passed through and use a belt slide or passed through and sewn?

If you would use a belt slide front and back on the crotch strap, would you attach the D ring on each of those slides or use a different slide for the D rings?

What kind of wing shape? Donut or horseshoe? How much lift? I have been looking at the 32 lb. HOG donut wing but I will also be keeping my eye out for a good deal on a used wing. I currently dive with 28lbs of weight in California waters.

When attaching the wing and STA if needed, do you use sex bolts or wing nuts?

What does it mean to you when using the term, balanced rig. Is that balanced in the way it helps you achieve proper trim, or balanced as far as over all weight and wing lift, or...?

Thanks in advance!

Keith.M:

I currently dive a back inflate Oceanic Excursion 2 BCD and although I am quite happy with it, I am also intersted in diving and becoming familiar with a BP/W set-up. My current tanks are steel LP 85's but I may be looking into going with HP 130's in the future.

I am looking to build this from the ground up rather then get one already preassembled.
Not a bad idea, but it's not going to save you any money.

I have several questions on things that I am just not clear on.
My answers/opinions will be in bold.

STA or not? Is the determining factor here if the plate has slots for the cam band(s)? Or, does it have more to do with pushing the tank out further from your back so you don't hit your head on the first stage.
That's the main determining factor in whether or not you NEED one. For people diving flexible setups or diving doubles and singles on the same backplate and harness, STA's are nice because you don't need to unthread your cambands....just pull two screws off, pull off STA and wing, replace with doubles setup and doubles wing. The STA does help get your first stage out of your skull as well.

Belt slides. Serrated or not?
Personal preference. On a single piece of webbing, you might want some some places. Are you going to use a grommet to hold the webbing fixed at the top of your backplate? If not, you'll want serrated belt slides at the top to keep your harness from moving at the top to reinforce the placement of the "Center" of your webbing. For d-rings, I like non-serrated. You'll play with exactly where you want them for a WHILE....and once you change weight or exposure protection, that position changes. Non-serrated belt slides won't "slip"....but they'll slide when you want them to.

I would be rigging the harness with a continuous piece of two inch webbing. Where the webbing comes down from the shoulder and goes out through the plate and back, do you use a belt slide on the back of the plate?
Some people do. I'd recommend away from it. If you don't use belt slides at the bottom, you can use the looseness there to add slack to your system to make donning/doffing MUCH easier. It adds slack to your shoulders by pulling from your waist band. Tighten your waist band and it'll tighten your shoulders down.

I was thinking I would also make the crotch strap as well but would either use a less rigid 2" webbing or go to one inch. Any recommendations on that.
You definitely do NOT want standard, stiff 2" webbing down there. Less rigid 2" is what I prefer, but that's just me. Neither are uncomfortable, that's personal preference.

On making the crotch strap, how do you form the front loop? Do you use a belt slide there or do you actually sew it closed?
It's "supposed" to be sewn...but there are no fixed rules on that. I like sewn because it gives me the warm-fuzzy I want.

How does it attach to the backplate? Passed through and use a belt slide or passed through and sewn?
At the back/bottom are usually a few slots. I run mine through there kind of like on a weight belt or Cam Band. Some people reinforce it with a belt slide. Adding a belt slide would keep it from slipping, but I've NEVER had a problem with mine slipping at all....even when I want it to slide. I don't sew mine, but I'm sure there are people that do. However, change your exposure protection and you'll wish it was on a belt-slide.

If you would use a belt slide front and back on the crotch strap, would you attach the D ring on each of those slides or use a different slide for the D rings?
I like having D-rings on the slide I use at the back. Too many slides is just a waste. For the front, I recommend getting it sewn. Actually, I recommend buying one commercially. It's much cheaper/easier/more secure.

What kind of wing shape? Donut or horseshoe? How much lift? I have been looking at the 32 lb. HOG donut wing but I will also be keeping my eye out for a good deal on a used wing. I currently dive with 28lbs of weight in California waters.
I like donut wings. I dove a Hollis S38 and am now diving a Hollis SMS100. I've dove horseshoe, but will always prefer donuts. No worries about getting an air pocket stuck in a corner.

When attaching the wing and STA if needed, do you use sex bolts or wing nuts?
Sex bolts whenever possible, IMHO.

What does it mean to you when using the term, balanced rig. Is that balanced in the way it helps you achieve proper trim, or balanced as far as over all weight and wing lift, or...?
Yup, pretty much. Not specific enough? That's part of the BPW charm . Honestly, it's both. Is your BPW a well-rounded, properly setup and chosen configuration?

Thanks in advance!
You're welcome

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Haha, I hope that helps.

Thanks for your response Victor!

I didn't really think it was going to save me much if any money. Rather want to put it together so it is "mine"...

Yes, I am planning on using a grommet behind the shoulders on the webbing to hold it fixed.

It will be a while if ever before I dive doubles so I imagine I will juts have to try it and see if I would be more comfortable with an STA.

I like the idea of not using the belt slides on the lower plate for the don/doff reasons.

Buying the crotch strap pre made might make the most sense.

My wing on my current BCD is a donut, I like your reasons there.

Laughed at your definition of balanced rig. That was great.

Thanks, it helped a bunch!

yeah what he said.

also part of knowing if you have a balanced rig is if you can ascend from depth with no air in your wing. if you ever have a failure you need to be light enough that you can get back to the surface under your own power, but still heavy enough for a proper descent without shooting to the surface when you reach 500psi.

Delta Hybrid System


I found this helpful. Even if you don't use their equipment its a good reference.

Balanced configuration means that total weight is split between fixed weight on the BP/wing and a weight belt on the diver such that removal of the BP/wing does not result in an uncontrollably buoyant diver.

N

Nemrod is exactly right about the balanced rig definition. Don't leave the harness loose at the points where it passes through the bottom corners of the plate; secure it there with tri-glides. You should set up your shoulder straps the length you want them and leave it there. You really don't want your shoulder straps to change when you tighten/loosen the waist belt. If you don't believe me, try standing up with a set of doubles and watch what happens if you have to unbuckle the waist belt....

Typically the crotch strap loop in front is secured with a tri-glide. That's the traditional spot for a D ring if you're scootering. I've never seen the loop sewn there, but I'm sure someone has done it. The vendors all have softer webbing for crotch straps, I like 2".

In general the GUE/DIR/Hogarthian approach to the harness is well thought out, and you might as well start there, making any adjustments you might want as you get more experience with it. So check out those sites for harness threading.

I would avoid the STA unless you need extra weight. The reason it exists is because early backplates for doubles did not have camband slots, and that was the only way to use a doubles plate/harness with a single tank. Now you have a choice. Most divers who have the harness correctly adjusted and the tank at the right height (whatever that is, for trim considerations mostly) don't have a problem with the tank banging into their head unless they're unfortunate enough to be using a DIN reg with an adapter on a yoke tank.

Check out caveadventurers for good deals on oxycheq set ups; usually its a plate, wing, harness kit, and cambands. Another excellent choice is the DSS stuff; that comes as more of an integrated system. The donut/horseshoe argument has been going on for years; the short answer IMO is that it doesn't matter as long as the wing is properly sized for single tanks. You're not going to get any air passing from side to side under the tank unless you're more-or-less upside down.

Have fun!!

My responses are similar to several others you have received.

Keith.M:

STA or not? Is the determining factor here if the plate has slots for the cam band(s)? Or, does it have more to do with pushing the tank out further from your back so you don't hit your head on the first stage? More the former. If your plate AND wing have slots, you don't need an STA. Some people don't like them, because they push the tank out from your body, and may contribute to trim issues, particularly with heavy (steel) tanks - you feel like you are going to roll over. Also, as noted, you can use a SS STA if you want to move more weight onto your rig, and off your waist.

Belt slides. Serrated or not? I have used both, but I have not found the serrated ones are necessary to hold position. They are more awkward to thread on.

I would be rigging the harness with a continuous piece of two inch webbing. Where the webbing comes down from the shoulder and goes out through the plate and back, do you use a belt slide on the back of the plate? Yes, both sides. Have rigged some plates without them, but prefer to put them in place to prevent webbing slippage. Also you didn't ask, but - you can burn a hole in the harness at the midpoint to accomodate the top hole in the BP, using a simple soldering iron, and you can buy a brass grommet kit from a hardware store, if you are so inclined, to protect the edges of the hole from fraying over time.

I was thinking I would also make the crotch strap as well but would either use a less rigid 2" webbing or go to one inch. Any recommendations on that? I have 2" straps and 1" straps. I prefer 1" straps - fully functional for me, even when scootering. I use 1" strapping and tri-glides from REI for crotch straps.

On making the crotch strap, how do you form the front loop? Do you use a belt slide there or do you actually sew it closed? I have done both. I slightly prefer sewing the front loop closed, and sewing the front D-ring in place. Either way works.

How does it attach to the backplate? Passed through and use a belt slide or passed through and sewn? Passed through, with a belt slide / tri-glide. That way you can adjust length.

If you would use a belt slide front and back on the crotch strap, would you attach the D ring on each of those slides or use a different slide for the D rings? Same slide in front. Depending on the length of the piece of strapping, I might use two separate slides in back.

What kind of wing shape? Donut or horseshoe? How much lift? I have been looking at the 32 lb. HOG donut wing but I will also be keeping my eye out for a good deal on a used wing. I currently dive with 28lbs of weight in California waters. I dive both horsehoe and donut. Both work. For HP steel cylinders, I slightly prefer a donut. I dive a 30lb wing for single cylinders, with a SS BP. Works for me with AL or steel. Works for me with 1mm neoprene (and no weight) or drysuit (with 20lbs).

When attaching the wing and STA if needed, do you use sex bolts or wing nuts? Wing nuts.

What does it mean to you when using the term, balanced rig? A rig that is weighted so that you can descend at the beginning of the dive, and still be able to ascend in the event of wing failure (i.e. no air in the wing).

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You have asked some very good questions! I have made all of my harnesses, and crotch straps, except one. All of my backplates, except one, have been purchased used, on eBay. And, I buy my hardware in quantity from Reef Scuba. I prefer to do it myself. So, while you may not necessarily save a substantial amount of money, it will probably still be cheaper than buying a commercial harness, and the learning value is significant. Let us know what you do, and how it turns out.

victorzamora:

Haha, I hope that helps.

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This was a great response!

To the OP... you'll never get it right the first, second or even third time. If you're like the majority of bp divers, you'll be trying out many different variations on your kit. Some will become permanent, some will be a source of embarrassment until you get them off (and quickly). Have fun. Think outside the box. Dive safely.

1'' crotch strap = fanny floss. Enjoy your giant strides with that one!

Balanced rig = able to hold stop at 15' with less than 500psi in your tank and no gas in your wing, yet also able to swim up w/ full tank from depth with no gas in your wing. This may or may not require some ditchable weight. 30ish lb wing is appropriate for just about everyone diving a single tank. Tobin from DSS can give you the long answer, if you're interested. I like doughnut, can dive horseshoe though. Doesn't matter a whole lot.

I like serrated triglides for the waist strap/backplate interface. Depends on your webbing, really. I have a big honkin' can light that would pull the webbing through on the right side every now and again. Switched to serrated, problem solved.