BP/W issue

[topflowerrubberforever]

Single Tank Adaptor

 

[TSandM]

When I started using Bob's BP/W setup, which has a DSS wing, I had a hard time getting the cam bands tight, too. I would pull on the loose end of the strap, and the tank would just rotate and the bands slip through the slots in the BP. But the tank would rotate clockwise, which to me would be to the left. But I guess it depends on where you're standing when you're assessing the rotation.

I found a couple of things that helped. One, I positioned the straps so the buckles were closer to the BP than to the back of the tank. That way, I'm pulling more or less UP on the strap, rather than across the tank. Two, I do the tightening with the BP lying flat on the ground, not with the rig standing up, and I'm not above putting a knee on the tank while I do it. And three, I put my left hand on the edge of the BP (the edge that would be on my right were I wearing it) and push down as I pull up on the strap. The combination of those three things now allows me to get the straps tight without shifting the tank with respect to the BP.

I think this rotation almost has to be happening while you tighten the straps. After you put the BP on, there's no force to cause the tank to rotate -- I mean, where is the torque coming from? Loose straps generally end up with the tank slipping down, rather than rotating, at least in my experience.

 

[gcbryan]

When I started using Bob's BP/W setup, which has a DSS wing, I had a hard time getting the cam bands tight, too. I would pull on the loose end of the strap, and the tank would just rotate and the bands slip through the slots in the BP. But the tank would rotate clockwise, which to me would be to the left. But I guess it depends on where you're standing when you're assessing the rotation.

I found a couple of things that helped. One, I positioned the straps so the buckles were closer to the BP than to the back of the tank. That way, I'm pulling more or less UP on the strap, rather than across the tank. Two, I do the tightening with the BP lying flat on the ground, not with the rig standing up, and I'm not above putting a knee on the tank while I do it. And three, I put my left hand on the edge of the BP (the edge that would be on my right were I wearing it) and push down as I pull up on the strap. The combination of those three things now allows me to get the straps tight without shifting the tank with respect to the BP.

I think this rotation almost has to be happening while you tighten the straps. After you put the BP on, there's no force to cause the tank to rotate -- I mean, where is the torque coming from? Loose straps generally end up with the tank slipping down, rather than rotating, at least in my experience.

One thing I forgot to mention which will probably make the picture clearer is that I have a 30 cu ft pony bottle mounted on the right. If the tank bands are loose the pony would pull the main tank to the right (or rather the top of the main tank goes to the right of centerline and the bottom goes to the left of centerline).

 

[Blitz]

I didn't see anything wrong with your threading at 3 tree. I don't that is it.

 

[Blitz]

Sorry, clicked too fast.

 

[cool_hardware52]

When I started using Bob's BP/W setup, which has a DSS wing, I had a hard time getting the cam bands tight, too. I would pull on the loose end of the strap, and the tank would just rotate and the bands slip through the slots in the BP.

I should point out that DeepSeaSupply has a solution for exactly this problem.

See http://www.deepseasupply.com/page12.html

Look down the page for the "wedge block"

If I recall correctly Bob is using his DSS wing on some other BackPlate, and may not be using all our goods as a "system"

The wedge block provides several benefits, one of which is to "lock" the cambands to the plate to prevent rotation around the tank when adjusting. They also provide a compressible element to make closing the buckles easier, and reduces the load on the buckles. The wedge blocks also prevent the camstraps from touching the slots in the backplate, to prevent wear.

Because of variations in the design of the center channels of various backplates, and the spacing of the slots, the wedge blocks fit only DSS plates.

Regards,



Tobin

 

[gcbryan]

I have those cam band wedges by the way but I've figured out most of the problem. I went on a dive today and made sure to get the bands extra tight and the plate didn't move as much.

After the dive I could see that the plate was slightly tilted but I couldn't move it (unlike yesterday) which tells me that today I probably didn't have the plate exactly aligned when I tightened the cam bands.

So today I did get the bands tight and the plate didn't move. Next time I just need to check the alignment of the plate after I've tightened things up. I thought I did that today but I guess not.

 

[gcbryan]

I didn't see anything wrong with your threading at 3 tree. I don't recall that is it.

The threading was ok but I just didn't get it tight enough.

 

[TSandM]

Tobin,

You're right. It's not one of your plates. Clearly the wedge block would solve the problem, but kneeling on the tank works, too

 

[MXGratefulDiver]

If I recall correctly Bob is using his DSS wing on some other BackPlate, and may not be using all our goods as a "system"

Quite so ... the rig I loaned Lynne was an Oxycheq/Koplin BP with DSS wing. The rig I let Gray try out was a DSS plate with Oxycheq wing.

My stuff tends to get mixed and matched a bit ... depends on what I feel like diving, or what I feel like loaning out to friends (right now I have two complete BP/W rigs out on long-term loan).

... Bob (Grateful Diver)