From BCD to BPW: The Evolution

[mmadiver]

This is really “old school”, but might spark a creative idea. The earliest tank harness were simple 1" cotton webbing with some 1½-2" wide pieces of webbing sewn to the shoulder area to spread the weight. They attached directly to metal bands — no backpack. We are talking Sea Hunt days here.

Not to old school. Navy still learns to dive this way.



Sent from my iPad using Tapatalk

 

[Akimbo]

Not to old school. Navy still learns to dive this way...

Oh no, they are really advanced now. The webbing is Nylon instead of cotton.

Seriously, the old harness isn't that bad on doubles but were really horrible on singles. You were lucky if they stayed within 20° of your spine.

 

[uncfnp]

Akimbo, you and everyone else has been ridiculously helpful. The discomfort is where the webbing passes over the front of the shoulder/chest area and transitions toward the backplate under the arm. You can't tell in the photo but I did sew on a length of soft 1 1/2 inch webbing to the end of the 2 inch that forms the waist band section. The 1 1/2 webbing then loops into the d-ring that is at the end of the shoulder section. It's where I added in the slide release buckles. With your rollers I can leave those out and sew it as a continuous length. Genius! It's a little complicated in an effort to keep it simple but worth a try. I've got plenty of webbing. It will be a few days before I can make a prototype but I'll let you know how it goes.

Ok, you lost me on the UHMWPE.

 

[lowviz]

...//... Ok, you lost me on the UHMWPE.

"Ultra High Molecular Weight Polyethylene" The good stuff, like in joint replacement parts.

 

[uncfnp]

"Ultra High Molecular Weight Polyethylene" The good stuff, like in joint replacement parts.

And where do I find " joint replacement parts" suitable for a backplate?

And no, I don't have it just lying about the office!

 

[lowviz]

And where do I find " joint replacement parts" suitable for a backplate?

And no, I don't have it just lying about the office!

-messing with you. Just order it from any plastics supplier in a suitable thickness for your purpose. But, yes, it is the same stuff...

 

[seaseadee]

I use it for making woodworking jigs and you can get it from a few woodworking places:

http://www.woodcraft.com/search2/search.aspx?query=Uhmw

 

[Eric Sedletzky]

Akimbo, you and everyone else has been ridiculously helpful. The discomfort is where the webbing passes over the front of the shoulder/chest area and transitions toward the backplate under the arm. You can't tell in the photo but I did sew on a length of soft 1 1/2 inch webbing to the end of the 2 inch that forms the waist band section. The 1 1/2 webbing then loops into the d-ring that is at the end of the shoulder section. It's where I added in the slide release buckles. With your rollers I can leave those out and sew it as a continuous length. Genius! It's a little complicated in an effort to keep it simple but worth a try. I've got plenty of webbing. It will be a few days before I can make a prototype but I'll let you know how it goes.

Ok, you lost me on the UHMWPE.

Sorry, I've been gone for a few days and just catching up now.

One thing you might want to check, and I can't tell from the photos, but make sure you don't have a half twist in your webbing from the shoulder down to the the waist.
The webbing should sit flat against your body all the way down from where it leaves the top slot all the way to where it goes into the lower angled slot.
Also, on your shoulder area, it looks like you might have quite a bit of bulk with the padding. This could be contributing to the pinch you're getting.
I have a lot of women your size using this plate and they have all settled on the straight one piece harness. They were skeptical at first but once used the whole webbing debacle goes away. Getting out of one is extremely easy. A lot of people put their arms back and try and slide the rig off. I train to put a hand underneath the harness strap and push out from the front. This way makes it easy and lightning fast and it even works with people who have shoulder issues like myself.

On the slide adjustment for the slots. I made some of those rollers like Akimbo suggested. They work great!
I used grey 1/2" PVC with a D-ring too, but it was a bastard to get the D-ring in, so I left it unglued. I figured if it was that hard to get in it's not coming out.
The slots on the newest plates are more rounded than models of the past. You might not even need rollers. They seem to slide pretty good on their own, but they're not super easy to slide. Kind of a happy medium.

E

 

[Akimbo]

Quick note on the UHMWPE, you will need to drill small holes in the plate for at least one screw per side to retain it. Any size screw between #6 and #10-32 should be fine. UHMWPE is really slippery stuff, easy to shape with woodworking tools, and amazingly tough. Most plastics suppliers stock it. My guess is ½" thick material would be fine. It is a lot more work to make this untried idea so I would test other alternatives first.

...Also, on your shoulder area, it looks like you might have quite a bit of bulk with the padding. This could be contributing to the pinch you're getting...

I agree with Eric, you might have too much bulk. Have you tried just using unmodified stiff 2" webbing?

I did observe that stiff webbing didn't make the shoulder to under-arm transition into the slots as smoothly on my female friend's small Freedom Plate as my plate does on me. It was tolerable on her, but she is at or above average height. Please let me know how your experiment works because it might improve her harness as well. We will be making some pool dives with it next month to refine her whole system for both tropical and cold water.

...The slots on the newest plates are more rounded than models of the past. You might not even need rollers. They seem to slide pretty good on their own, but they're not super easy to slide...

We tried my friend's plate without rollers but it hurt her injured shoulder too much to pull slack or do the "slip out" trick.

We also tried soft webbing that was more or less fixed at the lower slots, but that didn't work with her shoulder either. We didn't proceed with the UHMWPE test because the soft webbing was so limp when wet it would be harder to don in a suit. The springiness of stiff webbing really does help getting in the straps.

Thinking aloud here:
This was my first serious effort to help a female put her rig together. Their body-mechanics vary a lot from males and between each other. Their arms really do move differently. The old joke about girls throwing baseballs funny is founded in anthropometrics. They can learn to throw a baseball just fine, but not using the same techniques as the average male. That's probably the same reason men's shirts didn't evolve with back zippers. Compound all that with a shorter torso and injured shoulders and suddenly my bag of tricks is almost empty.

 

[lowviz]

...//... I used grey 1/2" PVC with a D-ring too, but it was a bastard to get the D-ring in, ...//...

Cut the slot, then throw it into boiling water for several seconds. -temporarily takes the fight out of it.

BTW, Lisa is using steel tanks. I'm guessing that a lot of the discomfort will disappear when she dives the rig.