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OP
Mat K
Registered
Thanks so much for all the advice - really helpful.
2airishuman
Contributor
Mat,
I have several pony cylinders. I have measured the buoyancy of each one in a tub of water using a string and scale.
Generally, when rigged with a regulator and sling, a full aluminum pony cylinder will be several pounds negative. HP steels will be significantly negative.
I would recommend redistributing weight from one side to another so that you are in proper trim. Whether you wish to also remove some weight from your belt is a personal choice based on your assessment of the relative risks of an uncontrolled ascent if the cylinder is lost, vs. the inherent risks and hassle of overweighting.
I have several pony cylinders. I have measured the buoyancy of each one in a tub of water using a string and scale.
Generally, when rigged with a regulator and sling, a full aluminum pony cylinder will be several pounds negative. HP steels will be significantly negative.
I would recommend redistributing weight from one side to another so that you are in proper trim. Whether you wish to also remove some weight from your belt is a personal choice based on your assessment of the relative risks of an uncontrolled ascent if the cylinder is lost, vs. the inherent risks and hassle of overweighting.
Technical divers have been carrying 2 al80 on the same side since about forever, without any real issue, yet you can always find people are arguing about "you need to shift weights for an al20". So there's really no worries to have there.
Removing weight because you're aluminium tank is negative when full, what could possibly go wrong.
(but then again, I'm on the side of "a 20cuft tank is not gonna change a thing").
What I wouldn't do however, is use a steel tank that is quite negative when empty, and I'm always surprised when people are using negative steel tanks as ponys. For those, depending on how negative they are, you might want to move weight around, but if you're not gonna remove some because "what if I drop the tank?", then it's a stupid choice in the first place imo.
Removing weight because you're aluminium tank is negative when full, what could possibly go wrong.
(but then again, I'm on the side of "a 20cuft tank is not gonna change a thing").What I wouldn't do however, is use a steel tank that is quite negative when empty, and I'm always surprised when people are using negative steel tanks as ponys. For those, depending on how negative they are, you might want to move weight around, but if you're not gonna remove some because "what if I drop the tank?", then it's a stupid choice in the first place imo.
3L x 200 bar = 600 litres = 21.18 cu ft
Good sized pony and shouldn't be an issue slinging it with a bungeed reg. I regularly dive with an S30 (~4.25L) and rarely notice that it's there.
Practice using it every now and then.
Good sized pony and shouldn't be an issue slinging it with a bungeed reg. I regularly dive with an S30 (~4.25L) and rarely notice that it's there.
Practice using it every now and then.
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