Weight belt/harness management in emergency

Marc T

Curious of what's your choise and solution (s) in case of complete flood of the loop?
Are you ready for such a situation?
I think its certainly one of the greatest danger in Rebreather dive ( for you and your buddy ) and a great difference with OC , more specialy in emergency situation.
Any thougt?

Marc

Nick uk.

BOV on FFM, plugged into a 7lt. alu, with a second stage for my buddy (or myself if needed).

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nigelh

Well it will probably have to go back to the maker.
I doubt that the wiring and stuff will like sea water.
And there's a new set of sensors.
Gonna be a tidy bill....



What?
You mean in the water?
I knew I was carrying bail out for some reason.

A flood is an easy fault. Hard not to notice. It's the insidious ones that worry me.

(edit)Weight: The loop is about 6L of gas. The wing is 22Kg. It's just a trim adjustment, not weight dumping time.(/edit)

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nigelh

sven

I assume your question is how to deal with the sudden negative buoyancy, when flooding the loop and/or the unit completely? If this is the case, here my thoughts:

At the bottom:
No problem, normal bailout.
Partially inflate SMB.
I may consider to drop my weight belt to get less negatively buoyant - it really depends on the deco obligations and distance to the anchor line, current, distance to dive buddies, ... The added negative buoancy from a fully flooded unit is slightly more than the amount of weights I am wearing.

On the anchor line:
Hold on tight! See above.

Blue water ascent on SMB:
Hold on tight!
Drop weights.
Start finning up quickly!

On the surface:
Drop the weights immediately.
Bailout.
Use SMB (a bit hard to inflate on the surface though, especially while struggling to stay on the surface!).
Then drop the torch, if I still can't establish positive buoyancy with manual inflation of the BCD.


This is what (my) logic would dictate. How would I react in reality? I don't know ... and I don't want to try either ...

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Marc T

[quote=sven]I assume your question is how to deal with the sudden negative buoyancy, when flooding the loop and/or the unit completely? If this is the case, here my thoughts:

Yes, thats the question.
I think that few people do ask themself what to do and configure their rig to self rescue.
More, I think its impossible to help his/her buddy if its impossible to drop his weight belt ( weight harness for exemple ) if the Rebreather is completely flooded.

I also guess that if your weight belt exactly compensate the buyoyancy of the loop, your still little heavy at bottom, but dramaticaly lightweighted at the end of a fast ascent.

A partial weight drop could be a solution?

Skipbreather

That is one of the selling points for weight integrated harnesses/ BCs. It is easy to drop only half of your lead worn that way. It gives you more control of the situation.

Down side is that if in a dry suit and you must ditch the rig for some reason (and exit wreck/ ascend using just a hand held stage) you had better be at the shot/ buoy/ anchor line. Otherwise you're on an express elevator to the surface.

Ken

Ben Field

Get one of these, best thing since sliced burnt bread!
http://www.apvalves.com/smbci.html

As an aside I've always carried a Lift bag, despite its obvious use for lifting spidge I figure you could always clip it to your harness and assist lifting yourself should you flood your suit/loop or rip the inflator out of your suit/wing.

Admittedly I've never tried it but I have "accidentally" lost an 18lb weightbelt from 35mtrs and I'd rather have some control (be able to dump gas from lift bag) than the extreme buoyancy of a belt drop.

Flooding a loop would be a jolly good time to have a buddy around IMO, can't think of a better time to have someone at arms reach with a bailout reg waiting and two extra hands to help and afterwards!

BEN

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caveseeker7

Go half way in between with a weight harness that has pouches.

I use the DUI Weight & Trim which separates the lead from the unit, making it easier to move either about on the surface. Weight position can be adjusted making it easier to balance, weights are distributed into four pouches that can either be emptied individually or dropped per side. The harness stays on when you remove the unit UW (which can be neutral either with gas in the loop or the wing) and prevents the diver from shooting to the surface. The bailout tank(s) can be moved from the unit's harness to the weight harness if need be.

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mortenkjerulff

Hi Mark.

Been there... but I was fortunate enough to be at the downline to the wreck.
However, I am using a drysuit and a wing, and I am very sure that inflating the wing is enough to get me back to the surface.

Morten

trob09

I stopped wearing ditchable weight a long time ago. I think the risk of losing it and blowing deco is greater than the risk of having excess negative bouyancy. It does require that you spend the time to get your weighting right (not to much or too little)

Somewhere along my tech training path I had to demonstrate that I could maintain bouyancy using only a lift bag. This was wearing heavy steel doubles (pressed steel 104's) and several (3 I think) stages. I haven't done empirical testing, but I can't believe that a flooded rebreather is more negative than that.

In this test we had to swim a course that had several depth changes and ascend to the surface with multiple simulated deco stops (the stops weren't required for the dive). This was done with all gas removed from the wing and suit. We did the same exercise using the drysuit as the only source of bouyancy.

If my wing alone wasn't enough to compensate for an unrecoverable loop flood, a lift bag or the drysuit could be pressed into service to get me to the surface safely.

T