Bailout and weighting

[Mark Davies]

What is the consensus on weighting when carrying multiple bailout cylinders?

More cylinders - more weight or leave it as it is.

I am currently weighted to hold a stop at 3m with just the CCR no gas in wing or suit.

 

[PeterN]

Depends on the cylinders...

If I get a bit floaty as my bailout runs out, I don't see that as an issue as I'll be going up anyway...

I add weight as I add Al BO tanks. I purchased a larger wing to accomidate the swings in weight.

Last thing I want is a struggle to stay down while on deco. Also I find that if I cut things too fine, I have to vacum pack my dry suit and am cold.

Peter

 

[steve6690]

Probably a dumb question, but here goes any way. Why don't we camband weight onto floaty cylinders to make them neutral when empty ? That way you'd never need to add or take away weight from your unit/belt. One less thing to forget

 

[PeterN]

Probably a dumb question, but here goes any way. Why don't we camband weight onto floaty cylinders to make them neutral when empty ? That way you'd never need to add or take away weight from your unit/belt. One less thing to forget

Not Dumb! One of my dive buddies does just that. This will only trim out the tank. It will not adjust the swing in weight when the tank is empty.

Peter

 

[steve6690]

Not Dumb! One of my dive buddies does just that. This will only trim out the tank. It will not adjust the swing in weight when the tank is empty.

Peter

That's what I was getting at. I normally dive with ali 7's which don't seem to be positively bouyant when empty. If I swapped to ali 80's I would need to add weight, so it makes sense to me to add the weight to your cylinders so that they are no more bouyant than the 7's when empty.

 

[barrygoss]

What is the consensus on weighting when carrying multiple bailout cylinders?

More cylinders - more weight or leave it as it is.

I am currently weighted to hold a stop at 3m with just the CCR no gas in wing or suit.

I'm neutral without any stages, when I've got stages on, I'll be negative and have to put a bit in the wing.

So on a bailout ascent, I'll go OC and start up, first thing to dump is the loop. that's 6L (6kg) of buoyancy sat on your back, that's more than enough to cope with floaty Ali80's with 15/55 in them.
(I'm lucky, on the kiss there is a suit dump just behind my head, I'll spin that from + to - and it'll dump the loop through the one way valve just like your drysuit does)
When up to 20m and on to the 50% I'll bag off the deep bail, I'll clip the 80 with 80bar in it to the dsmb line and watch it head for the surface. (and yes I've done it, it was during a bailut drill and it was getting lighter and annoying me, when I was finished with it, it got sent up. I was chuckling for the next 30mins wondering what people were thinking about with an ali 80 arse up on the surface)
Then it's just managing 3 buoyancy sources, the wing, the suit and the loop. (unless you flood the loop to remove that problem, but that's a bit extreme for training ;-) )
So weighted neutral for a 3m stop without bailout and everything else is adds and omits during a bailout.

B

 

[Garspeed]

For me, weight is set for no stages so if you drop them, sent them north when done or hand them off to buddy you are still properly weighted. When descending with stages I only dump enough gas from wing and lungs to get moving south leaving some in wing to counteract for heavy stages. On way north to shallow stops this can be released if required to hold stops but normally not an issue as stages are still heavy if unused.

Cheers
Gar

 

[MartyC]

If bailout gets floaty, clip them off to your smb line and send them up, deal with them later when you hit the surface

 

[barrygoss]

I'm not sure that the European/CE spec'ed Ali cylinders (40/80 cu ft or 11.1L) are as buoyant as the US versions. Think there heavier..... my 80's are 14.3kg (WT). With a valve & reg added their not that floaty when near empty.....

What's in them? Mine weren't that floaty, then I made them deep bailout and stuck 15/55 in them. Breathe that down and I got to bag it off. Weirdest thing I've ever seen. Clip to smb line and watch it ascend
B

 

[Bobjr]

Mark

I'll answer your question with a question: Why carry weight for something that you will rarely use and can dump (more usually hand off or send up / clip off to a line) in a bailout situation?

weight yourself for the stuff that you can not get rid of (ie your CCR only) - it would be easier than OC because less swing in gas.

 

[DSix36]

The very minimum that I will ever carry is one Aluminum 40 for BO. I weight myself so that I can hold a 10' stop with an empty wing and drysuit, and then add a couple of pounds for suit inflation.

I will not change my weighting for more tanks, but I will adjust for undergarment changes and for the difference between fresh and salt water.

 

[Mark Chase]

I use steel 10s which are neutrol when empty and a single AL80 which is positivly boyent when empty

Ill weight for a 6m stop no tanks.

The steel 10 with Trimix in it is very slightly neg when full. The Al80 is about 2kg neg when full of Nitrox so i am diving at least 2kg heavy all the time but I dont find it a problem. I prefer not to dive AL80s full of trimix because they float up too much when full. OK for all tanks left but a PITA when diving left right.


ATB

Mark

 

[MartyC]

I'm not sure that the European/CE spec'ed Ali cylinders (40/80 cu ft or 11.1L) are as buoyant as the US versions. Think there heavier..... my 80's are 14.3kg (WT). With a valve & reg added their not that floaty when near empty.....

Appreciate that Jon, I suppose what I was trying to say was that if you did have buoyancy issues, then a potential fix was to remove the buoyant items from your person, I know its not ideal, but its better than hitting the surface bent as helloke:

 

[nickb]

What's in them? Mine weren't that floaty, then I made them deep bailout and stuck 15/55 in them. Breathe that down and I got to bag it off. Weirdest thing I've ever seen. Clip to smb line and watch it ascend
B

Hmmm. Empty tanks that once contained deep bailout are floatier than empty tanks that once contained shallow bailout. How's that work?

 

[alin]

What is the consensus on weighting when carrying multiple bailout cylinders?

More cylinders - more weight or leave it as it is.

I am currently weighted to hold a stop at 3m with just the CCR no gas in wing or suit.

Hello Mark.
I think it's a good question as many people tend to ignore this aspect.
Depends of what kind of tanks are you using. You're weighted at the moment so you can do a 3 mt stop without gas in the wing or suit. Very good. Now imagine how deep you wanna go, how many bail out tanks you wanna take. Now jump in the water with those bail out tanks empty and try to make the stop on 3 meters. Try to adjust the wights over there. If the crap hits the fan and you'll have to bail out, you don't wanna struggle to stay at 3 meters, with 3 or 4 tanks, after a 100 meters dive for example...

 

[barrygoss]

Hmmm. Empty tanks that once contained deep bailout are floatier than empty tanks that once contained shallow bailout. How's that work?

If they aren't quite empty its down to the displacement of the tanks giving an upthrust and the weight of the gas left in them giving the down thrust,

Take 80 bar left in an ali 80 (11l)
80 bar of air weighs 1.06Kg
80 bar of 50%O2 weighs 1.098Kg
and 80 bar of 15/55 weighs 0.56Kg

so half a Kg (2lb) buoyancy swing depending on what gas is in them when 80 bar left.

That 2lb may be enough to make a tank go buoyant and also explains why an Ali80 full of O2 is such a bitch to handle (3kg of gas)

Regards,
B