babycover
Registered
I see. Would suspect that is the case. I will tighten the sliding D-ring and see how it go.But with Faber steel tank which does not change buoyancy as ali tank, what is the benefit of sliding D-ring?
How to locate the optimal height for sidemount cylinder bands
- Thread starter DevonDiver
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- bands configuration sidemount
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All tanks change buoyancy as you use up air.
babycover
Registered
that's new to me. how does it change? heavy top? or the other way around?
runsongas
Contributor
the benefit isn't as large with steel tanks between sliding and fixed drings. the sliding dring gives multiple possible attachment points which is more useful for an aluminum tank that needs to be moved further along the harness multiple times as it empties to keep good trim whereas a steel tank does not get very positively buoyant and might only need to be moved once or twice down from the hip drings.
OP
DevonDiver
N/A
A cylinder exists in 3 buoyancy states, during the dive:
1) Negative
2) Neutral
3) Positive
All cylinders start negatively buoyant. When clipped, they'll hang.
As gas is consumed from the cylinder, the amount of negative buoyancy reduces.
For as long as the tank remains negative, no matter how slightly, it continues to hang down.
Aluminium tanks can become positively buoyant when sufficient gas is consumed from the tank.
Most steel tanks do not become positively buoyant, even if emptied. Invariably they will always hang. There are a small handful of exceptions.
Tanks that become positively buoyant will float. Any tank that's at all positively buoyant, even slightly, will float.
Tanks float up from the base. Buoyancy is not uniform across the cylinder. This is because the top of the cylinder has a heavy chrome/brass cylinder valve and heavy regulator 1st stage on it.
The base of the tank can (and for aluminium, usually does) becomes floaty, long before the entire tank becomes positively buoyant. This is because the weight of the valves/regulator etc at the top is supported.
Neutral buoyancy is momentary - the tank passes from positive to negative in the space of a single breath. For sidemount purposes we can pretty much disregard neutral buoyancy of tanks.
So... tanks are either hanging or floating. This factor dictates only two attachment points; one to the rear for when tanks are hanging and one to the front for when tanks are floating.
I'm not sure where this 'incremental' myth comes came from. Positive or negative buoyancy... hanging or floating tanks... take your pic.
Sliding D-rings are unnecessary from a cylinder trim perspective. There is no need, nor benefit, to "incrementally" moving them.
The reason to have sliding D-rings is if you find it more awkward to manipulate and operate bolt-snaps. Using a sliding D-ring removes the need to unclip, relocate and re-clip the cylinder bolt snaps.
For some divers, such as those in cold water wearing thicker gloves, that can he beneficial.
For divers without an impediment to their dexterity... and who are well trained, with attention to detail, in equipment operation.... there's little or no need for a sliding D-ring at all.
1) Negative
2) Neutral
3) Positive
All cylinders start negatively buoyant. When clipped, they'll hang.
As gas is consumed from the cylinder, the amount of negative buoyancy reduces.
For as long as the tank remains negative, no matter how slightly, it continues to hang down.
Aluminium tanks can become positively buoyant when sufficient gas is consumed from the tank.
Most steel tanks do not become positively buoyant, even if emptied. Invariably they will always hang. There are a small handful of exceptions.
Tanks that become positively buoyant will float. Any tank that's at all positively buoyant, even slightly, will float.
Tanks float up from the base. Buoyancy is not uniform across the cylinder. This is because the top of the cylinder has a heavy chrome/brass cylinder valve and heavy regulator 1st stage on it.
The base of the tank can (and for aluminium, usually does) becomes floaty, long before the entire tank becomes positively buoyant. This is because the weight of the valves/regulator etc at the top is supported.
Neutral buoyancy is momentary - the tank passes from positive to negative in the space of a single breath. For sidemount purposes we can pretty much disregard neutral buoyancy of tanks.
So... tanks are either hanging or floating. This factor dictates only two attachment points; one to the rear for when tanks are hanging and one to the front for when tanks are floating.
I'm not sure where this 'incremental' myth comes came from. Positive or negative buoyancy... hanging or floating tanks... take your pic.
Sliding D-rings are unnecessary from a cylinder trim perspective. There is no need, nor benefit, to "incrementally" moving them.
The reason to have sliding D-rings is if you find it more awkward to manipulate and operate bolt-snaps. Using a sliding D-ring removes the need to unclip, relocate and re-clip the cylinder bolt snaps.
For some divers, such as those in cold water wearing thicker gloves, that can he beneficial.
For divers without an impediment to their dexterity... and who are well trained, with attention to detail, in equipment operation.... there's little or no need for a sliding D-ring at all.
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What is your recommendation on the most optimal attachment configuration for Faber steel cylinders? They behave worse in this regard.
babycover
Registered
ok, some update from me, after several trial with sliding D-ring, no way the sliding D-ring can hold the Faber steel cylinder. no matter how tighten you can get with the bungee, the d-ring just doesnt hold the steel cylinder at a fix position. At the moment, i clip it on my butt ring, but i thinking of adding fix D-ring to waist belt and clip the tanks there. sliding D-ring might be good for stage, deco, ali bottle.
unless someone teach me how to tighten the sliding D-ring more, but then it will be really difficult to move it, if it too tight
unless someone teach me how to tighten the sliding D-ring more, but then it will be really difficult to move it, if it too tight
Ozwald
Contributor
Man....advice from Andy being called condescending and belligerent? That's madness but I guess there's all kinds. Tell you what, listen to what the guys says.....it's church as far as I'm concerned. Whether its an improvement to an existing system or otherwise (we are all aware that these systems are absolutely perfect and need no teaks) the guy speaks from experience. One day Mr Davis we will meet!
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