Inadvertent but valuable weighting lesson

[boulderjohn]

When people speak of "skin bends," they are usually referring to a form of DCS that has nothing to do with dry suits. What Pete is describing is the uncomfortable (and possibly worse) result of not keeping your dry suit properly inflated.

It happened to me once when I cracked my argon bottle to check the pressure on the button gauge on my argon bottle and then forgot to open it all the way. Everything was peachy keen as I began the descent, which was quite rapid. As I continued the simple regulator on the argon bottle could not handle the increased pressure and I could not inflate the suit. I recognized the problem quickly and reached down to open the valve. Those few seconds of descent were enough to have my skin bruised with the wrinkle marks of my dry suit. It was not really painful or even uncomfortable, but it sure looked funny.

 

[TMHeimer]

To add to the lessons learned: As newer divers continue to do more dives, they learn how to better handle buoyancy, breathing & safety stops so often need less weight as they become more experienced. This is especially true since many new divers are over weighted to begin with.

It never hurts to a full on buoyancy check once in a while.

I think this is true only if divers are overweighted to begin with. Experience does of course meaning getting better at those things, but will not allow you to drop weight if properly weighted to begin with. It just makes you a better diver. Several have agreed with me on a recent thread somewhere.

 

[boulderjohn]

I think this is true only if divers are overweighted to begin with. Experience does of course meaning getting better at those things, but will not allow you to drop weight if properly weighted to begin with. It just makes you a better diver. Several have agreed with me on a recent thread somewhere.

I agree. The primary reason dives are able to drop weight as they get more experience is that they were badly overweighted in their classes and earliest dives.

 

[The Chairman]

that was in reference to their inherent buoyancy. Obviously you have to inflate to maintain the bubble size, but the point was that if you can maintain neutral buoyancy at 20m, then you can maintain it at 2m. Very much unlike a wetsuit that loses buoyancy as a function of depth

Now this statement makes sense. You can maintain the same buoyancy by adding/subtracting air as your depth changes.

 

[NYCNaiad]

I think this is true only if divers are overweighted to begin with. Experience does of course meaning getting better at those things, but will not allow you to drop weight if properly weighted to begin with. It just makes you a better diver. Several have agreed with me on a recent thread somewhere.

Newbie divers can be over weighted. I was. However, newbies often don't know how to control their breath & some don't recognize how to fully empty their bcd so even if they do a buoyancy check during the earlier days, it's not always accurate.

 

[Landau]

I have always been good at fully emptying my BC. Fully emptying my drysuit on ascent has been the tricky part. Takes a few contortions to get the bubble to to valve. I'm also starting to feel the bubble better.

 

[Storker]

it's red blotchy and itches like hell. Don't do it. It's caused by Boyles Law because dry suits undergarments compress with depth.

...and is called suit squeeze. Skin bends is cutaneous DCS, a totally different animal. They have nothing to do with each other.

Fixed your statement, BTW

Now this statement makes sense. You can maintain the same buoyancy by adding/subtracting air as your depth changes.

What's so (not literally) cool with drysuits, is that as you descend, you add gas to your undergarments to avoid suit squeeze and keep your undergarments lofted. That keeps your suit's volume constant, and you hardly ever use the BCD/wing to stay neutrally buoyant. As you ascend, you vent gas from the suit to stay neutral. This is not the same as using the suit instead of the BCD for buoyancy, because the weight of your gas is balanced by the air in your BCD, and you vent that slowly during the dive to stay neutral as you carry less and less gas.

 

[Patoux01]

You'll find a "scholar example" of the result of a suit squeeze here http://www.ffessm-provence.net/upload/plongee_scaphandre/files/Neptune/Analyse_CRFI_2017-002 Squeeze v4.pdf (scroll down a bit in the page).

Didn't take him long to get to that state, nor was he very deep.

However, this has nothing to do with "skin bends". It matters a lot, because skin bends mean the diver should (imo) at least be put under O2 and watched for symptoms. If it results from a squeeze, then I'm much less worried.

You can also be slightly squeezed without it being really noticeable, until you remove the suit and undergarment and notice you can see all the seams and folds of your undergarment on your body


Oh and also, a good way to not lose your weight pouches is... not having them! You're welcome

 

[Storker]

You can also be slightly squeezed without it being really noticeable, until you remove the suit and undergarment and notice you can see all the seams and folds of your undergarment on your body

My wicking layer is this. It has happened - more than once - that I've noticed a nice, decorative waffle pattern on my skin. I've taken that as a sign that I could well add a couple of kilos to my belt.

 

[Beau640]

In drysuit diving: Weight=Warmth.

You can always dive with less weight and the resultant less air in your dry suit, but do you really want to?

I guess I dive dry slightly different.

I only put enough air in the suit to loft/eliminate squeeze. No more. If I'm cold with this then I just wear heavier undergarments rather that add more air. This allows the least amount of air in the suit which allows for the smallest air bubble to deal with and the least amount of weight to dive with.