Info Impact of a drysuit flood

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@CT-Rich i've had it happen without a boat involved. tore the neck seal then tried to use the wing to compensate but then the inflator hose fitting elbow somehow cracked and fell off of my rental xdeep wing. no ditchable weight since I was running HP doubles and a steel plate. had to use smb and some finning to keep it together.
I’v seen those elbows and never trusted them…

That’s why I never listen to the people that say “a balanced rig shouldn’t need ditchable weights”
 
Yeah I install pull dumps in all my bcs and wings it they're not already there set them up with
two inch slack before activation, and there is bladder protection, strain relief, at the top of all

Diving sometimes especially shore in conditions not dived by most and here I am still talking
with the other pull dumpsters with open minds understanding of gear not gulping flavor aid

Pull dump, quickest safest way to dump when you are confronted with a fast buoyant ascent
 
I like seeing people experiment and find out for themselves.
I think a lot of people repeat ideas or concepts that are questionable, yet they are entirely convinced of the their validity, even though they know that they have no first hand knowledge to back it up.
 
I use a regular BC (Black Ice) and not a wing, which uses weight pouches on the BC. I can open either compartment on one of the 2 pouches without dumping the pouch entirely and selectively remove weights so as to not "pop". I've never needed to test that (knock on wood) but I would prefer to try selective removal in the event a powered swim to the surface is not working by itself.
 
I flooded my membrane suit at 65m depth in februari in a marble mine of 8 degrees C. I could still hold my bouyancy with the wing of my ccr. But my trim was a mess and the way back to the exit was a hell because you cannot swim normally. It ended with a CO2 hit, but further nothing to worry. The wing had enough lift capacity.
 
The worse part of a total flood for me was getting out of the water.
 
The worse part of a total flood for me was getting out of the water.
The worst part for me was realizing that piece of crap was not reliable enough to make plans with. Aqualung fusion constantly had problems with seals and I had been told by the shop that it could be upgraded to user replaceable and it wasn't. Total waste of money.
 
Based on a recent thread regarding a balanced rig, a question arose as to just how much buoyancy is lost when a drysuit floods. It just so happens that I wanted to directly measure my trilaminate drysuit buoyancy while wearing my Fourth Element Xerotherm+Arctic undergarments (together) before I take a trip to Lake Michigan. (Knowing this makes it easy to be correctly weighted with various combinations of gear I use, whether that's a single AL80, single LP85 steel, or double versions of either; AL or steel backplate or sidemount, etc.) Mission accomplished: wearing just the suit (lofted with my normal amount of air, exhaust wide open), I needed 31 lb of lead to be neutral.

For any dive, I want to be weighted such that I am neutral with an empty wing & about 1 lb of air in the tank (about 500 psi in an AL80). (If I need to use that reserve air, I can breath shallow and still remain neutral.) For a cold-water, single-tank dive, I would use my LP85 steel tank. Because the steel tank, stainless backplate, lights, etc. partially offset the positive suit buoyancy, I only need an additional 16 lbs of lead to be neutral at the end of the dive. However, if I am neutral at the end, I will be about -7 lb at the beginning of the dive (the weight of the non-reserve gas in my tank), so I put a bit of air in my wing to compensate. The positive wing and suit buoyancy exactly balance all the negative equipment/lead/gas, by design. This is what I consider "properly weighted" (though I concede that it's useful to be a couple lbs heavier in some situations).

I had a bit of time left... so I opened the zipper underwater and completely flooded the suit. I mean COMPLETELY, making sure no air was left. I then removed the belt... and stayed right there on the bottom. With a fully flooded suit, I had the same buoyancy that I have in a swimsuit alone -- basically neutral. However, that means before dropping that weight belt, I was negatively buoyant by 31 lbs and could not have kicked to the surface. If I were on the above dive wearing this suit and both suit and wing were to completely fail, I would be at -38 lb (suit + gas).

So can I get out of this pickle? Dropping my 16 lbs of lead would be a good start (net of -22 lbs now). I carry a 6 ft DSMB that conveniently develops about 22 lb of lift (taking me to neutral). What if I lost the DSMB? (I would actually carry 2 for such a dive.) Honestly though, I would try to salvage some buoyancy out of the wing and/or suit by putting the damaged portion lower in the water. I expect I could become positively buoyant without too much trouble. If not? Well, that's one reason I like to dive with a solid/capable buddy. Their fully-functioning wing is only supporting 7 lbs of gas weight, leaving plenty to help drag my unlucky butt to the surface.

My initial desire for this post was to simply report that I lost the entirety of my suit buoyancy when it was completely flooded. However, this being the Basic Forum, I decided to illustrate some of the thinking I feel a drysuit diver should undertake. (A similar issue is faced by wetsuit divers, so don't ignore all this -- you'll lose buoyancy due to suit compression at depth.) What are the ramifications of your equipment choices? Can you deal with a wing failure? Can you deal with a total suit failure? What options -- plural -- do you have if they both somehow fail? Do you even need ditchable weight at all? Is it safe to ditch ALL your lead (without inducing an uncontrolled/runaway ascent)? Play the 'what if' game from the comfort of your chair.

If you haven't seen it, I strongly urge you to check out the Optimal Buoyancy Computer. That is a tool available for download that was created specifically to explore this topic, and my heartfelt thanks to @rsingler for that. It's certainly useful to help pin down the amount of lead you need, but having insight into how much of that can/should be ditchable and additional backup buoyancy required may well be critical someday.
What resolution did you come to?
 
https://www.shearwater.com/products/peregrine/

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