Info Cam Buckle Assembly Instructions

[Akimbo]

I think the explanation for Akimbo's more than additive effect of two bands, is that, if you watch how a tank slips out for a single band, it first twists sideways. That has a large lever arm on the band and stretches at with a huge mechanical advantage, and then it slips down. As it slips down and the band gets loose the tank twists more and finally slips out.

The second tank band not only adds extra friction but prevents the tank from twisting.

Adam

True, but our observations lead us to believe there is also a binding effect between the two bands. We ran a rope through an overhead pulley, tied to the harness, and jerked the rig up about 2' and let it drop 2'. The cylinder would slide a little on each cycle with a single loose band -- we estimated at the bottom of the drop. With two bands the cylinder would move more in relation to the BC at first and then nearly stop relative movement as if the bands were tightened. The closest analogy I can think of is the binding effect of a clove or rolling hitch compared to an overhand knot.

These "experiments" were not well controlled but interesting. Band tightness was "estimated equal" rather than measured. The surfaces were sprayed with a garden hose about the same. We didn't get too carried away studying the observation since there are so many other arguments justifying two bands.

I haven't looked that close at jacket BCs in years. Do most accept a second band as an option or with a simple modification?

 

[mselenaous]

Thanks for the well illustrated reference source. I test my DM candidates on cam band re-assembly since there is always a student or a diver in rental gear that disassembles everything without knowing how to reassemble it

. It's usually the with the loose tank.

 

[LeadTurn_SD]

Very nice, thanks for taking the time to produce such a detailed reference Akimbo.

Regarding jacket BC's being able to accept two bands? I "believe" those that have the internal plastic backplate may be able to.

Before switching to BP/W, I was able to "convert" our Mares "poodle jackets" to accept a 2nd band. The slots were already in the plastic backplate, and the "punch-outs" were present in the BC fabric for a 2nd band.

My guess is that there is probably a common "source" for the plastic backplates that the BC manufacturers use in their jacket BC's.... so probably many jacket BC's using the internal plastic plate do have the ability to be fitted with a 2nd band?

Best wishes.

 

[BennyM]

Or use the SP BC band.

 

[Banyan]

I'll admit to not having my cam bands thread this way and, worse, never having thought of simply leaving the cam bands on the tank to stretch them out. So I've been adjusting the bands on my new BC every three dives or so. On the plus side, a few days after rethreading my bands, and setting aside a day to stretch them out, I came across a new diver who for some reason had undone the cam bands of his rental BC in order to make it easier to put on his tank. He gave me a "wow" when I put it back together without apparent effort. Thanks Akimbo for making me look good!

 

[Akimbo]

... I came across a new diver who for some reason had undone the cam bands of his rental BC in order to make it easier to put on his tank,

I can understand why they thought it might be easier to put the bands on with two loose ends, because it is, just not with conventional cam bands. That is why I like the Highland bands, especially after modifications described in this post. It is also a factor why the ScubaPro bands mentioned are popular.

See this thread: http://www.scubaboard.com/forums/ge...811-do-you-have-either-these-tank-straps.html

Mods start in post #25 but the whole thread may be of interest.

BTW, thanks to you and others for the kind remarks.

 

[Jax]

You do good work, Akimbo! :cool3:

 

[D_B]

sticky

 

[Akimbo]

sticky

Scubaboard read your mind! OK, I asked. But they were kind enough to make it sticky after a couple of weeks.

 

[sparky923]

Thanks Akimbo---

I'm going to print out a laminate a few of the key pictures to place in my log book--- just in case!