How to locate the optimal height for sidemount cylinder bands

[DevonDiver]

I thought this might be helpful for some sidemount divers.

How to locate the optimal height for sidemount cylinder bands for loop bungees:

How to find the Optimal Height for Sidemount Cylinder Bands

 

[tbone1004]

been saying that for years! thanks for getting a blog post about it.

Note that this works much better for aluminum or floaty LP cylinders and if you're using HP steels you may have to put the lower attachment point a bit farther down with a longer leash for trim purposes, but that's the spot where you should be starting. You can also just measure on the rig itself if you don't have a buddy to measure while you're wearing it

 

[Remy B.]

What about when you clip them to the top D-ring of your harness if you don't have Loops ?, I do have bungee cords to put it around the valve knob in order to keep them near my body.

 

[scubasmacks]

very helpful, thanks!

 

[decompression]

Andy, what do find is the optimum cord length for the waist bolt snap? I usually use a "fist", 3-4 inches of cord between the bolt snap and the hose clamp.

 

[DevonDiver]

@decompression - It depends a lot on the other aspects of your configuration.

Firstly, I'm primarily talking about aluminium cylinders. Secondly, I'm assuming the goal is to have the cylinders snug against the torso... feeling 'a part of you'... with less wobble and play... and certainly not dangling.

I use loop bungees, so I find that the shortest possible leash is beneficial. It needs to counter the cylinder torque caused by the bungee. About 1cm... a "little finger", just to give the boltsnap enough freedom to move unimpeded.

With continuous, or even independent, bungees, a slightly longer "fist" leash may be preferable. That's the approach I used to have, until a few years ago.

The band height may be influenced by the length of the leash you choose to employ.

But, in general, I don't see any significant advantages in having a longer leash and setting your bands at a different height because of that.

 

[Remy B.]

I ask again, in a different way.

Do you have other method for people that use D-rings in the shoulders instead of only bungee cord ?

Another questions

How will a bungee setup do in rough waters, regarding un-clipping your tanks and hand it over to the Surface assistance ?

I seems uncomfortable to hand the tanks by the regulator/valve or by the Bold Snaps/clip located to mid tank, grabbing it by the handle/carry strip was kind of unstable in choppy waters for me

How do you do in case of having 2 Deco tanks, you use as well only one bolt-snap at mid tank and tight the top with the same bungee ?

 

[DevonDiver]

Bungee is an inherent feature in sidemount. It's necessary for proper positioning and movement of the cylinders.

As mentioned, an additional 'hard' attachment at the top of the cylinder can be achieved by a cord choker with either a permanent bolt snap or a removable double-ender.

I've never experienced, observed or even heard about issues with sidemount in rough water. The bungee should keep the cylinders secure and trimmed snugly against the side torso.

The only issue really occurs out of the water, where cylinder dry weight comes into effect... and that can mean a choker/snap setup gives a hard point attachment that takes the strain off the bungees. In-water, the cylinders aren't particularly straining the bungee at any time.

If passing cylinder up to a boat were problematic for any reason, it's easy to employ a 'lifting-rope' type system. The boat crew lower a rope with snap... the diver connects it to the cylinder valve choker... and the boat crew lift the tank up.

I've seen some divers setup deco/stage to use an additional loop bungee. But the most common methods are either (1) regular stage rigging or (2) sidemount specific rigging that uses a neck bungee choker w/snap and a lower snap via thicker/longer bungee from the cylinder band (see below)...

 

[babycover]

Hi Andy, I did exactly this however on the Apeks wsx 25, is the bottom band clip onto the D-ring on waist belt or the dropped Dring where the butt pocket place?

 

[DevonDiver]

... on the Apeks wsx 25, is the bottom band clip onto the D-ring on waist belt or the dropped Dring where the butt pocket place?

It depends entirely on your bungee method and tank material.

Loop bungees only really work well when the cylinders are out onto waist D-rings. That counters the torque given by the loops and keeps them trimmed.

That's true for either steel or Ali cylinders.

If using continuous or independent bungees, it all comes down to cylinder material:

- Aluminium goes to the waistbelt, so you can move it - rear to front D-ring - to counter cylinder buoyancy.

- Steel can go on a buttplate. But it's also workable with waist D-rings.

If using ring bungees, only with steel cylinders, it'd go on the buttplate.

If using steel cylinders, the choice of using the buttplate can be especially beneficial if you're of short height, or you have a sidemount BCD that isn't adjustable for spine length - it allows you to keep the cylinder bands lower.