Drysuit exhaust valve question

[vixtor]

I just did today my second drysuit dive (and the first one with my own drysuit).

During the dive, I have encountered an issue that I would like to hear your opinion about.

First, i have to say that I was a little underweight. I did my first dive with the borrowed suit and some thin undersuit, having 8kg (17.6 lbs) of lead. It was way too much. Now, with my suit&undersuit (a normal 100g one, but thicker than the one that I have tested initially), I entered with 4kg (8.8lbs), then added 1 more kilogram (having 11 lbs in total). While at surface I was ok, under water, when I had to add a little air, i was a little buoyant

Because of this buoyancy, it was really important for me to empty as much as possible of the air in the drysuit while ascending.

My question is the following: is there any arm position where you can raise the valve, without raising more the lower part of the arm? Because of the way I was raising my hand, I was still having some air bubble in the extremity of the arm, that was hard to vent out. Of course, a little more lead to compensate for this residual air would have solved the problem, but is this really the right solution?

 

[RJP]

Do the "chicken wing" thing:

- fully extend arm straight down, so all air is out of arm
- without raising arm at shoulder, bend arm at elbow bringing hand up to armpit
- THEN raise arm, with elbow still bent, until your upper arm is horizontal
- No need to point your elbow UP since you want the valve at the highest point

This forces air out of forearm, and by bending elbow helps prevent more air from flowing there when you raise your arm.

Also helps if you break trim by going a little "head up" and roll a bit down on the right side so that your left side is a bit higher.

Ensure the valve is at the top of your upper arm when raised. Sometimes they can rotate around to the front/back and end up NOT being at the highest point.

Lastly, use your BCD for buoyancy control and just put enough air in your suit to keep the squeeze off. Having only the smallest amount of air necessary in the suit makes it that much easier to manage venting when you're ascending.

Takes a little getting used to, but comes pretty quickly with experience. You'll notice the amount of weight you need decreasing once you're more accustomed to drysuit use.

Welcome to the wonderful world of diving dry!

 

[vixtor]

Do the "chicken wing" thing:

I think this is what I was trying to do, but my harness was a little bit too tight (i still have to adjust it some more), and it was restricting my movement.

Ensure the valve is at the top of your upper arm when raised. Sometimes they can rotate around to the front/back and end up NOT being at the highest point.

Good tip; i had the impression that the valve is a little oriented towards the bottom, but didn't thought this could be possible. Any tips for moving it back, except for pulling it in the required direction?

Lastly, use your BCD for buoyancy control and just put enough air in your suit to keep the squeeze off. Having only the smallest amount of air necessary in the suit makes it that much easier to manage venting when you're ascending.

that's what I do.

thanks

 

[dave4868]

Of course, a little more lead to compensate for this residual air would have solved the problem, but is this really the right solution?

RJP's tips are excellent, but don't shy away from adding a little more lead, too.

Regarding weighting, the "right" solution will depend on one's goals because there are trade-offs to wearing the "minimum" weight, one of which you clearly described.

I'd say that adding one or two kilograms of "excess" weight will certainly make it easier to maintain neutral buoyancy at the end of the dive, especially if your suit or undergarments tend to trap air. Ascending may tend to get ahead of you a bit quicker, but you'll have a quicker solution because your "excess" air can be quickly vented.

A couple kg's of "excess" weight (and its resultant "excess" air) will have relatively little negative impact considering that, even without it, one starts the dive with significantly more air in the buoyancy device(s) to offset the initial weight of breathing gas in the tank.

Today, as it happened, the weight I wore on the first dive turned out to be very close to the "minimum" needed for the combination of undergarments I was trying. As a result, near the end of that shore dive, I often had to gyrate out of my horizontal swimming position in order to vent enough air out of the suit.

For the second dive, I put on 4 more pounds (a little less than 2 kg's) and maintaining gradual ascent was easy with just a little roll to raise my shoulder valve.

Seemed like the "right" solution to me....

Dave C

 

[mikemill]

Have someone video you while you vent. I had that done it was an eye opener.