weight(ey) problem

[dave sel]

Hi,

I had a bit of a mishap over the summer (not serious thankfully) and have been struggling to idetify the cause and remedy.

I dive on twin 12's with a 7 litre stell stage for deco. The stage is a fairly new development, but I've done about 50 dives or so with it.

The biggest problem I found when I started was being overweighted, and there were one or two very alarming descents and a lot of hard work at depth where the weight was really noticeable.

I ended up with no weight at all, even in the sea. Everything was fine until the last time when I was unable to hold the 9 metre stop (stops at 12 and 15 were fine, as were pyle stops and bouyancy on the dive generally)

I'm failrly certain there was no trapped air in the wing, and I'd not had this problem before.

Clearly I need to weight check before using again, my current thoughts are to add the weight of the gas used on the dive, and I'd appreciate any thoughts on the cause and suggestions anyone might have

ps, I was bent but luckily rapid first aid and recompression (and, I think, the deep water stops) helped prevent it being seriousundefined

[Andy Phillips]

Weighting should be done without the stage, when you add the stage you add gas to the wing.

I do this in fresh water and add 4Kg's for the sea.

Andrew

[nigelH]

Originally Posted by dave sel

The biggest problem I found when I started was being overweighted, and there were one or two very alarming descents and a lot of hard work at depth where the weight was really noticeable.

I ended up with no weight at all, even in the sea. Everything was fine until the last time when I was unable to hold the 9 metre stop (stops at 12 and 15 were fine, as were pyle stops and bouyancy on the dive generally)

OK. You're underweight not overweight. (A typo?)

31L at 232bar weighs 8.4Kgs so you must be at least 8.4Kgs negative at the start of a dive if you empty the wing. Of course you don't empty the wing or you'd drop like the anchor. No weight on twin 12s would normally be 4 to 5Kgs underweight so you'd get down OK but probably blow the stops as you did.

QED: put the lead back. Do a weight check with the tanks virtually empty so you are in stop mode having used the reserve. You should be able to hold depth just below the surface with hardly enough gas to move the needles. Then, when you rescue your buddy from certain death, you can do all the stops and bring him back alive. You will need about 8+L in the wing as you descend but that's normal for twins and a stage.

Bad news on the bend. I'm glad it all worked out ok.

nigelH

[dave sel]

thanks, overweight was right in the first message - thas was when I first started and still had a full weight belt