Buoyancy Control - done with your BCD/Wing or Drysuit?

[Finless]

[quote=[b]Quote[/b] (Dominic @ May 26 2003,13:45)]

does it never occur to them to wonder why an autodump is so named..?

Some of us "thems" have cuff dumps.

Sorry, spent too long doing it my way to change.

I totally agree with the way to start ascents - although I must admit I tend to overdump on the way up and end up having to pump some more back into the suit. Slowing the ascent rate down to 4 mtrs a minute has made my ascent profile a lot less "bouncy".

[markg]

<font color='#000F22'>all this time i've been doing it wrong !
5'6&quot;, 12 stone, 12kgs weightbelt, twin 10's on a buddy commando. only use suit for bouyancy.
never had a problem even at 55 mtrs in wastwater.to get moving up just take a big breath. suit not full of air to the stage of bloated.
re inverted ascents, if you're using a drysuit you really should &nbsp;know how to get the air out of the legs
just my opinion of course

[Wacker]

<font color='#8D38C9'>Re: suit bouyancy

On a recent trip to Stony Cove I was diving with two sport divers both in dry suits,
One was very new to dry suit diving!
Having  just dived for 28 min on the Staney Garth and just having deployed his delayed SMB the new dry suit diver got inverted.
He re orientated himself and I checked he was ok he confirmed this and we went on.
During the problem his budie had got seperated ,I checked again that he was ok and again he gave the ok .
I turnd to find the other diver  and back again,all I could see was a mass of bubles and a rapidly assenting diver .
The other diver and I made a fast but safe accent and found our mate at the surface,
Iasked him if he felt ok as he had just done A VERY RAPID ACCENT FROM 18M.
He recond he was ok but I kept on telling him he should at the least see a doctor if he felt any joint pains or odd as he could have decomprestion sickness.
well to cut a long story short after a week he found a pain in his arm and it started to get worse!
He ended up in the pot at plymoth for the whole of the next week!!
(catogary 6 bends)
he was very lucky and now still has a problem with one of his fingers.
He had been using his dry suit as bouyancy and had his auto dump set fully open.
He said every thing happend so quickly
HE WAS AT THE SURFACE BEFORE HE COULD DUMP THE AIR THROUGH HIS NECK SEAL.

VERRY LUCKY MAN

BEWARE

WACKER    

[Fiona]

<font color='#0000FF'>

Originally Posted by [b

Quote[/b] (Wacker @ May 27 2003,23:32)]Iasked him if he felt ok as he had just done A VERY RAPID ACCENT FROM 18M.
He recond he was ok but I kept on telling him he should at the least see a doctor if he felt any joint pains or odd as he could have decomprestion sickness.
well to cut a long story short after a week he found a pain in his arm and it started to get worse!
He ended up in the pot at plymoth for the whole of the next week!!
(catogary 6 bends)
he was very lucky and now still has a problem with one of his fingers.
He had been using his dry suit as bouyancy and had his auto dump set fully open.
He said every thing happend so quickly
HE WAS AT THE SURFACE BEFORE HE COULD DUMP THE AIR THROUGH HIS NECK SEAL.

VERRY LUCKY MAN

BEWARE

WACKER    

He was a very lucky man, although luck shouldn't come in to it.  This just shows that we all need to be aware of anything which may result in a DCI hit.  Anyone who has an accent which has not been controlled should as a matter of course receive O2 at least as a precaution.

There are alot of divers out there who still think that to admit to an error and request O2 is not the done thing.  The sooner the diver receives O2 the better the outcome.  Stoney has O2 on site.

[Justin Owen]

Just a bit of info some of the more inexperienced (i.e. like me) may find useful.

We were in Fron last night providing surface cover before a short dive. Been practicing reducing my weight, and after being comfortable in Vivian with 10kg, decided to go for 8kg on the weight belt. Took a while to get down, but at 10M was ok, though had a lot less air in suit than used to. As we finned along, we can only assume we swam into an area of warmer water - myself and my buddy found ourselves floating skyward and no matter how much air we both dumped from our suits we both ended up on the surface.

Until I change my kit configuration, 10kg is now my weight for fresh water! Will allow me a bit of air in suit for warmth, and give me a bit of leeway should conditions result in me being a bit light at any point!

Another quick comment - anyone notice that on a buddy jacket (i have commandoTD) that the sections of the bladder that come up over your shoulders trap air? You can dump one side with the pull dump, and the other with corrugated hose, but only having one pair of hands personally, it can be a pain if your trying to stop an ascent.

[Dr Stevil]

<font color='#0000FF'>Hmmm...Long thread, not much time at the moment.

For my diving it's Suit mostly, wing as and when required.

If you need buoyancy, put it in your suit, that way it provides buoyancy and warmth plus reduces squeeze , in the BCD is only does the former. Plus, itreduces task loading as on the majority of my dives, I only have to think about one source of air to adjust when ascending

Contrary to an earlier post, it doesn't matter where you put your air, suit or BCD, it isn't going to make any difference to the amount of lead you carry, you ain't gonna change the laws of physics you know

My wing is empty until I go below 30-35 metres at that point I add a fairly small amount, upon ascending this is dumped first, then from 30 up it's all back to the suit.
This has worked well for me for several years now - nil problemo

Chee-az
steve

PS having re-read the thread there are some pretty big issues as far as I'm concerned:

1) problems with inversion - bloody hell!! &nbsp; &nbsp; if you can't cope with an inversion and correct it with relative ease, you need to get back to the shallows and practice until you damn well can. Anyone diving with me in shallow water will notice that from time to time I will invert myself fully for a bit then correct it: one, because it's a fun thing to do and two, because it's a skill which really should be practiced regularly

2) Justin - don't fin downwards, it increases your susceptibility to narcosis and DCI, try dropping nice and slowly parachutist sty-lee

3) Finless - I'm with you on that, but some people do &quot;dive by concensus&quot; but lets not go there

4)And finally a bit of a rant....
Gah!!! &nbsp;Please please please....will all inexperienced divers ignore these comments that XX lbs or kg is &quot;a lot&quot;, &nbsp;who for ? Repeat after me &quot;We're all individuals....&quot;

Regardless of what some folk advocate we're not all the same with identical kit requirements. For example, one time a trainee turned up to the dive site (Crummock, which is two hours from home) with 6lbs of lead .

&quot;Where's the rest of your lead ?&quot; I ask

&quot;Well Scouse Pete told me in the pub he only uses 4 or 6 lbs of lead so that's what I brought....&quot;

&quot;Hmmmm do you have his twin 12s + SS BP? No? Do you have the same amount of body fat as him? No? &nbsp;Are you wearing exactly the same undersuit/thermals/layers as him? - No? well you sit there until some other properly kitted out trainee has done their dive and we'll see if they'll let you borrow their weight belt&quot;

&quot;boo hoo hoo ....&quot; wails the chubby little trainee, (whereas Scouse Pete is built like a greyhound)

See what I mean? &nbsp; You can't compare apples and oranges.

[Andy Phillips]

Hi,

Just wanted to say (I think again), it all changed for me when I added two stages and Argon, the suit just does not give enough lift, no which way. I have to say, the discovery was a bit un-nerving, I jumped in and sank, I pused the button on the suit and carried on sinking. Luckily it was only in 15M so when I hit the bottom in a cloud of silt I was still relativly calm.

Couple of things I learn't from this;

1) those people who say you can use the dry suit as back up to the wing have no idea what they're talking about
2) it doesn't matter how hard you push the button, it will only let so much air through, the rate of inflation is definatly slower than the rate of desent
3) it was time to change the way I dived and use the wing as the primary source of boyancy control

As for task loading, I thought this would be an issue, but as all of us who dive deco know assents are not done at a million miles an hour, there is plenty of time to adjust a bit here and a bit there. Also, auto-dumps on the suit remove this issue anyway. All you have to do is open it up a bit just before you bag off and Bobs your Aunties lover. Mark dives a cuff dump, I was watching him over the weekend,, and he seemed to have absolutley no trouble at all.

Andrew

[Dr Stevil]

<font color='#0000FF'>

Originally Posted by [b

Quote[/b] ] it all changed for me when I added two stages and Argon, the suit just does not give enough lift,

Er...Andy I think we're into the realms of comparing apples with pork pies there mate. Still, a useful adjuct to remind less experienced divers that whatever they use during the dive, always bung some air into your BC before getting in to the water. Also, it terrifies me when I see trainees anywhere near the waters edge when their primary reg is dangling all over the place. Always always have it either in your hand or (preferably) hanging out from the corner of your mouth, that way if you fall over/fall in the reg is there straight away.
One day I was telling this trainee as she emerged from the water &quot;Get that reg back in your mouth!&quot; when a sudden wave swept up and knocked her into a gully on the rocky shore. fortunately she landed sitting upright, but if she had landed face down it could have been a different story.  

Originally Posted by [b

Quote[/b] ] those people who say you can use the dry suit as back up to the wing have no idea what they're talking about

Ahem...I'm sure you didn't mean that the way it reads Andy, for non-technical (or up to 30m) diving with a correctly weighted diver the DS usually should (and IME does)  provide ample buoyancy during the dive, excluding the beginning and end points. However, IMO it doesn't matter how someone chooses to do it, as long as it works well for them.

Justin, if you find it hard to get down with X amount of lead at the start of a dive, how are you going to control your ascent at the end of a dive when your tank is less full and therefore more buoyant don't get too hung up on reducing the amount of lead you carry.

Chee-az
Steve

[Andy Phillips]

Hi Steve,

To be honest I agree and disagree, reminding trainees about just about everything is essential, the three classics are, jumping in without air in the BCD, jumping in without / or removing at the surface the reg, and removing the mask as soon as they surface, all Bad.

I agree with you about singles and the BCD, if the weighting is correct then just removing the squeeze should be enough to give correct boyancy.

The point behind the story was really to help those who are moving onto the twins with stages bit. Like yourself I have done enough dives to remain, for the most part, reasonably calm as things are going a bit pear shaped. Even so, this one was a bit un-nerving, it just hadn't crossed my mind that the suit would not control me, it was always OK with just the twins.

The bit about using the suit as back up, with twins and stages, oh yes I mean that, if someone actually say's that, either they have a very different suit to me, or they have not tried it. I can tell you absolutley, if my single wing failed I would not get back without ditching something, I have tried this at the NDC with 80 Bar left in the twins from 14M. I have a twin bladder wing, the second bladder worked, but it only just provided enough lift. Just for info, I had an extra 4 Kg's on this weekend, I did the experiment without them, but, it was in fresh water.

I am not trying to be rude, (although doing this without trying seems to be an unfortunate talent of mine) I am trying to pass on the information. If it helps one diver make an informed decision about what or how they do something then it was worth typing.

All the best,

Andrew

[dave archer]

Originally Posted by [b

Quote[/b] (FionaB @ May 28 2003,09:41)]Anyone who has an accent which has not been controlled should as a matter of course receive O2

 That's going to be news to our Scots and Brummie friends then!!  

Not wishing to trivialise though - Fiona is absolutely right, the guy should have had O2 after that ascent...

Dave.