Problems dumping drysuit in trim

[WhiteSands]

I try to use as little gas as possible in the suit when diving, typically two short bursts on the inflator button every 12-15m or so, or a burst or two when the suit gets too tight and restricts movement or breathing.

However, on ascent, the gas in the suit expands and I have problems dumping it, especially that last little bit.

I've thought about it and have an idea why. When swimming in trim, my feet are at the highest point. Naturally gas wants to migrate there.

My own feedback signal for dumping is when I feel my fins getting loose on my boots, then I know there is a little too much air in the suit. I like to feel the squeeze on my feet at all times when diving dry.

When I raise up my shouder/arm to dump, I notice nothing comes out when I am swimming in trim.

So far there are 2 things that kinda work for me but I'd like to find a better way.

1. Raise up my left arm up straight up for a few seconds to let all the gas collect there. Then I chicken wing my arm to try to get rid of the gas. How much the gas fills up my sleeve also lets me know how much gas there is in the suit. I try to keep the volume of gas in the suit to less than half my forearm. However, even with this method, it is hard to get that last bit out.

I know the response will be that the suit needs some air in it. Once I get in trim again, the air goes back to my boots and makes my fins feel loose, which isn't good.

2. Get into an upright position and dump. I can feel the squeeze on my feet when I do this right away, which is great. This works the best, but messes with my buoyancy control. Obviously this method cannot be used in a confined space.

I was wondering if there is a better way to this? Physically if the feet are up, the gas is bound to want to go there, even if my shoulder is raised to dump air. What is the proper way to do this?

I'm using a Santi E-motion with soft boots btw.

 

[PfcAJ]

Make the dump valve the highest point and carry on. Sometimes you can migrate the bubble up your torso a bit without getting completely vertical of course, but don't sweat not being in 0degree perfect trim to dump gas. You gotta dump it so do what it takes.

 

[Dr Dog]

I agree...You gotta do it.

M exhaust valve is on my bicep, I would prefer it was moved over 4 inches...but nothing I am going to send the suit in for. So sometime I have to get into a 45 degree angle to get the air into my upper body. I still find I need to "roll" into a 45 degree angle on my side to get it to vent after a deep dive( lots of air in there).
My suit is pretty tight fitting, so air does not move very freely..It can be a bit of a struggle to vent it out after adding a lot for a 100" or deeper dive

 

[TSandM]

The simple answer is that you cannot move air out of your feet, without dropping your feet lower than your dump valve. Even in a cave, you will have to do this; if the physical setting precludes it, you have to swim around with your boots full of air (which is unpleasant). This is one of the reasons why a lot of us who dive dry in caves run our suits quite squeezed in that environment, although we may not do that in open water.

On an open water ascent, it is perfectly fine to go very briefly out of trim to move air up to the dump valve.

I counsel our student and the people I mentor not to weight themselves so they are neutral at 500 psi with an empty wing AND empty suit. That means two things: You are committed to getting the suit totally empty to maintain a safety stop with an empty tank, and you will be horribly squeezed at the end of the dive, when you are coldest and would really like your undergarments lofted. I prefer to weight myself for an empty BC and a suit that is at its usual, comfortable volume, which will generally need a couple more pounds. If you weight yourself that way, it's generally not too difficult to get the excess gas out of the suit at the end of the dive. But it will require briefly dropping the feet.

 

[rjack321]

Part of the problem is that you are diving underweighted. Add 2lbs, put more gas in your suit and dive comfortably without trying out every last molecule of suit gas every 10ft of ascent.

Add fin keepers to avoid the loose boot feeling when you have that little bit of extra gas in your suit. 2lbs is about 1L of suit gas.

 

[eelnoraa]

If I think about it, here is what I do if I feel air is in my feets. I first straighten my left knee, roll a little toward the right side with right arm raise up, air will move from left foot to right arm. Then I straighten right knee, roll a bit toward left side, drop right arm at the same time, now air from right foot will move to left arm, air in right arm will move to left arm, where the dump it. The amount of roll needed is very little to move air this way, and won't be out of trim much

 

[WhiteSands]

Thanks all for the great advice. Will be trying out your suggestions on my next dive.

 

[Gareth]

I just drop out of trim. Physics is physics and gas will not voluntarily travel downhill. Straighten you legs, point your toes, and give the gas some time to rise to the upper part of your body by dropping out of trim. The you can go back into trim and dump the gas.


Sent from my iPad using Tapatalk HD

 

[Peter Guy]

TSandM, that very highly educated, superb diver and teacher, who is, by all reports, a true scuba goddess, wrote:

On an open water ascent, it is perfectly fine to go very briefly out of trim to move air up to the dump valve.

Although I do not have the reputation, knowledge, experience, etc. of TSandM, I must comment -- Bull pucky.

On and open water ascent, what difference does it make what attitude your body has as long as you are comfortable, able to maintain your place in the water column and able to assist your buddies (teammates) when and if necessary?

This obsession with being "in trim" is just that -- an obsession. Diving is about (first) Safety and (second) Enjoying yourself. Don't sweat the trim -- PARTICULARLY when doing an ascent in open water!

BTW, your buoyancy control shouldn't be effected (very much) by trim/attitude. If it is, something else may well be going on.

 

[Dsix36]

I got caught in a vicious cycle of loss of buoyancy control because I was obsessed with staying in trim. It was not a pretty picture and my 90' - 20' - 90' - 20' - 90' profile with complete disregard to my deco ceiling was downright scarey. How I managed to not get bent like a pretzel is beyond me.

Screw this damn worry about perfect trim at all time at all costs and do what it takes to remain safe in the water. If is is meant to be, then with time and experience it will happen.

No, I am not DIR, GUE, GOD, or any other. I am just another idiot that likes to dive and prefer to come home safely.