+ Buoyancy of new light euro cylinders.

[Rydive]

Originally Posted by eey_ore_9

You need to look at your drysuit undersuit or wetsuit. POSITIVE BOUYANCY = Drysuit & undersuit approx 8kg
wing gas 3kg so 8+3 = 11 kgs positive, therefore your already 11 kilos positive before you start.
NEGATIVE BOUYANCY Twin 12s 2KGS X2 =4KGS
BACKPLATE 3KGS
BREATHING GAS 3KGS
WEIGHTBELT 3KGS SO 4+3+3+3=13KGS LEAVES YOU 13 -11 =2KGS NEGATIVE (AT START OF DIVE BEFORE YOU USE ANY GAS) This is the reason why most use a P weight or V weight (approx 3kgs) on twinset and 2 to 4kgs on belt.I found that trying when id got 35 bar on twins at 6 metre shelf, loaded up with weight then take weight off until i could fin to surface was best for me. I then divided weight between twinset and belt.Im overweighted at start but i can still dump weight to make it to surface. At end of dive im nicely negative but still like to drop a bit more weight off,I think that will come whem im more confident at holding stops to within 0.5 metres

Thanks for that... I think you might need to check the weight of your gas though. Nearly 7 kilos in twin 12's, not 3. I.e. a 7 kilo shift from full to empty.

Which come to think of it, makes me wonder if all of these people saying that they only wear a few kilos are telling porkies.

Bearing in mind the weight of the gas, the very minimum that you would have to carry if you were neutral at the start of the dive with full cylinders and no weight would be the weight of your gas... 7 kilos give or take.

So even if your rig was 7 kilos negative, that would still mean that you were either neutral in a drysuit (impossible), or had to add more weight, no?

Am I missing something?

[trakrat]

Originally Posted by Rydive

Thanks for that... I think you might need to check the weight of your gas though. Nearly 7 kilos in twin 12's, not 3. I.e. a 7 kilo shift from full to empty.

Which come to think of it, makes me wonder if all of these people saying that they only wear a few kilos are telling porkies.

Bearing in mind the weight of the gas, the very minimum that you would have to carry if you were neutral at the start of the dive with full cylinders and no weight would be the weight of your gas... 7 kilos give or take.

So even if your rig was 7 kilos negative, that would still mean that you were either neutral in a drysuit (impossible), or had to add more weight, no?

Am I missing something?

try having a look at your undersuit
i use forth element and i'm just slightly over weighted in salt and very over weighted in fresh this is after cuting down on weight of all my kit
and i have no lead on my kit
twin 12s neoprene drysuit oms wing
in fresh i have to change from my ss reel to a plastic spool for dsmb
ok i'm not as big as you 5'8'' 13.5 stone
but it sounds to me that its undersuit because you say that at 10m you begin to feel heavy this would be beause your undersuit is compressed and no longer trapping loads of air
it's beging to warm up now so try wearing a tracksuit under your drysuit and do a weight check if this helps you drop lead then go buy forth element undersuit
hope this helps
rob

[Fiona]

Originally Posted by Rydive

I'm still needing about 15kg to hold a stop!

Originally Posted by wreckferret

Hi,
I need 35Lbs to feel comfortable.

Originally Posted by warmwaterdiver

That's what I thought. I was diving 10kg until Mal did a proper weight check with me and I was able to shed 7kg.

[wreckferret]

Fiona,

I have been diving for 15 years plus and have done lots of weight checks but it always ends up @ 35Lb, if I could use less lead I would (bad back).

I am very envious when I see people with no or only a few pounds of weight.

[eey_ore_9]

I was just giving an example (APPROX) of negative and positive weights re cylinders and gas etc. Obviously i dont know if your suit +undersuit are 8 kgs positive or the weight of any other items you have, but you can work it out if You have the info. I just found the formula very helpful and it worked for me. Just trying to be helpful and giving a different perspective, what works for one does not neccesarily work for another but if you try you can then rule it out of the equation.

[Rydive]

Originally Posted by eey_ore_9

I was just giving an example (APPROX) of negative and positive weights re cylinders and gas etc. Obviously i dont know if your suit +undersuit are 8 kgs positive or the weight of any other items you have, but you can work it out if You have the info. I just found the formula very helpful and it worked for me. Just trying to be helpful and giving a different perspective, what works for one does not neccesarily work for another but if you try you can then rule it out of the equation.

Definately, as I said, thanks alot for the advice. I wasn't trying to be funny or anything, sorry if it came accross like that.

[eey_ore_9]

No worries, no harm done as i didnt read it that way..! I just felt I had to explain the format Of my content.I dont think anyone who dives twinsets are weighted perfectly (your a clever bloke so i think you've done the maths) Your either going to be light at the end or heavy at the begining of a dive.You can get close but never perfect hence lots of things come into the equation..Is your wing big enough to lift the excess weight at the start,what if your wing fails is their enough lift in the drysuit (which is your redundant lift).!How much lead do you want to carry on a belt to make it easy to remove? That ones a big factor!Do you carry extra weight incase your buddy becomes too light?Theres so much to work with.I know your an experienced diver and know your maths but its so much worth while doing shallow weight checks, say 6 metre shelf near empty tanks(obviously with someone who can bale you out) weight up so your just negative to drop nicely to bottom.then get partial fill to say 50 bar and go to where you can drop to 15 metres and take with you your buddy and extra weights and add on weight on the bottom until you can just swim comfortably to surface.you might find you have to remove weight as i did making me neutral or positive at 6 metres.I found that the first 4 metres was the sticking point for me once beyond that i could descend quite rapidly,Im still fine tuning though.Good luck and stay safe,enjoy your diving.