DSMB Filling

[Garf]

Originally Posted by MartyC

Yazzy,
Leave him alone
I am intrigued though, Mala if you use your bc dump to put air in the bag; a) how do you do it? b) dropping air out of your bc will defo affect your bouyancy - please explain.

you're dropping air out of your bc but its going into the bag. Until you let go of it you're not going to have any buoyancy issues. Then you're going to have some. I don't like this technieuq as the moment you let go of the bag you have to contend with two things at once - making sure the line is running freely, and adjusting your buoyancy to compensate for the big bag of air you have just let go of.

Our DIR team uses closed circuit ones like Bardo describes. We fire them up without making any changes to our buoyancy whatsoever, so we only have the to check. Any change in depth is quickly met with ridicule and public humiliation. It's quite an effective training technique

[Janos]

Originally Posted by MartyC

Yazzy,
Leave him alone
I am intrigued though, Mala if you use your bc dump to put air in the bag; a) how do you do it? b) dropping air out of your bc will defo affect your bouyancy - please explain.

The air goes into the DSMB. So no overall bouyancy change until you let got of the DSMB.

Janos

[Bardo]

Originally Posted by Janos

The air goes into the DSMB. So no overall bouyancy change until you let got of the DSMB.

Janos

...as Garf says, therein lies the problem - as soon as you let go of the bag, you start to descend!

Personally I'm surprised there hasn't been a single comment about how life is so much easier if you use a crack bottle SMB! Personally I don't like them as they're a) bulky and b) a pain to fill conventionally should you forget to refill the thing before the dive (something which I've seen happen on a number of occasions).

My favourite type of SMB is still the closed circuit type. If you're worried about disconnecting your drysuit feed (!) then - for the non-DIR types - you could always run an inflation hose off a deco/bailout bottle - easy!

[Miss Roxy Chablis]

I use the closed circuit type bags which I inflate with my drysuit inflator hose.

This is not without issues. You're bringing the bag quite close to you body whilst you fill it before moving it out to arms length to release it. There is also the issue of having to disconnent and reconnect your drysuit hose. I don't like having the potential for a lot of fast moving loose line anywhere near my body. It's taken quite a lot of practice to get this slick in midwater - but now its easy - unless Mal's watching me - then its a total disaster!

I tilt downwards and fin gently as I fill the bag with the hose to counteract the change in buoyancy as I do it. Your only talking a few seconds at most to fill it adequately so that its full on the surface. We're talking about the standard 4.5 foor Halcyon bag here. As Jason points out - you can fill the 3 foot ones with a big lung full using your mouth and that works fine. They're not big enough to use in the Ocean tho - too small to be visible unless it flat calm.

I was diving the U480 with someone yesterday who uses the exhaust gas inflation method into an open ended bag with a baffle. We bagged up off the wreck (55m) and starting winding the reel in to move up to our first stops at 39m. We met the bag coming back down again at 33m - much to our amusement Pretty much proved to me that this method just doesn't get enough gas into the bag - even at these kind of depths - to make it stand up on the surface. It wasn't an issue of technique - he's an excellent diver and made what I thought was a perfectly good job of the deployment.

The crack bottle DSMB's are a piece of cake to use - but just take up a hell of a lot of space and I hate having anything dangling off me.

Skippers seem to really like the Divesign's name tapes stuck to the top of DSMB's BTW - makes it very easy for them to see who's who and where.

Accepted norm now to use on Orange bag for normal deco and send a Yellow bag up the same line for an emergency that needs drop gas.

Bit of a ramble - HTH

[MartyC]

"you're dropping air out of your bc but its going into the bag. Until you let go of it you're not going to have any buoyancy issues"

Sorry Garf, I kind of figured that one out
Just the way it was described sounded odd.

[endoman]

It's a lot of air to dump from a bc isn't it?

[mala]

Originally Posted by MartyC

Yazzy,
Leave him alone
I am intrigued though, Mala if you use your bc dump to put air in the bag; a) how do you do it? b) dropping air out of your bc will defo affect your bouyancy - please explain.

yea yazzy leave me alone-didn't mean to overstep the mark!

i stick the auto air thingy in the bag and dump air into it.
bouyancy remains the same untill the bag is released as the air has only moved from on bag to another.
sure when it is released i have to squirt some air back in bc or suit.
just means that i don't need to rush to release it.
don't always do it just mainly.

[Miss Roxy Chablis]

Err yes - that really would be method number 476 on my preferred list

[Bardo]

Originally Posted by Howard Payne

Err yes - that really would be method number 476 on my preferred list

You and me both, Howard - sounds just the trick for holding those stops!

[Miss Roxy Chablis]

No 477 is using flatulence through a one way valve in the arse of my drysuit - then deflating the bag when back on the boat by sucking the gas out of it orally. You don't want to know what method no 478 is...