Drysuit dump valve and shutdowns

[elan]

I think that when I reach for my left post during a valve drill, some air leaks from the valve.

Do you guys maybe rotate or change your trim so you don’t leak from the dump when closing the left post?

No rotation or change of trim is required. If you are in a horizontal trim arched back and your head is up - paying attention to your buddies the valve is easy to reach. You do not even need to change your body position. If you lose a lot of air to affect your buoyancy you have too much air in the suit. If you need that much air to keep you warm you need thicker undergarments.
Drysuit is for warmth - BCD is for buoyancy.

 

[elan]

I am new to doubles, I have about 50 dives with them at the moment, and I will be starting ANDP next spring to kick off my tech journey. My instructor has been tech diving for longer than I have been alive and he dives with drysuit as primary bouyancy. I am not 100% devoted to any particular type/style of diving so I keep an open ear for when I come across problems. So far drysuit as primary has worked for me but if I come across issues with this style of diving I will be looking at changing to see if that solves the problems.

Dry suit for buoyancy works ok when you dive recreationally and lose some 3-4 lbs of air during the dive. Diving technically with say 60mins at 100ft where you still use heavy nitrox will easily require you to use up 8-12 lb of gas. My drysuit buoyancy with a light undergarment is about 22lb. Adding another 12lb of lift at the beginning of the dive to compensate for the weight of gas will require me to purchase some popcorn for my buddies so the can eat it while being entertained by my “controlling buoyancy with my dry suit”dance. Jokes aside wings are designed to compensate for the swing of tanks buoyancy. You can also balance the load on the harness and plate side to side when you attach extra tanks on one side. You just cannot do it with the suit efficiently.
Even with a single tank wing I can easily put two more al80 stages on one side and stay flat by shifting the air to that side of the wing.

You might want to relearn your habits before your ANDP.

 

[BlueTrin]

No rotation or change of trim is required. If you are in a horizontal trim arched back and your head is up - paying attention to your buddies the valve is easy to reach. You do not even need to change your body position. If you lose a lot of air to affect your buoyancy you have too much air in the suit. If you need that much air to keep you warm you need thicker undergarments.
Drysuit is for warmth - BCD is for buoyancy.

I dive with the valve open.

The air loss I have currently is not large enough for me to drop (though I am not sure whether it would be true if I do multiple drills in a row)

I am asking because I was curious and wanted opinions and different viewpoints on whether I was doing something incorrectly.

Also I think the air loss is a bit smaller if I do the valve with the elbow in front than with the elbow on the side, but I’d have to ask my buddy or record to be sure

Maybe I am arching without noticing in one of the two.

My previous drysuit was a bit too small and I had to work against the fabric to reach the valves. I think it made me possibly arch a bit to compensate and maybe I was going out of trim while reaching the left post. I just got a new drysuit and will try it at the pool, will see if it is better.

 

[beester]

I am new to doubles, I have about 50 dives with them at the moment, and I will be starting ANDP next spring to kick off my tech journey. My instructor has been tech diving for longer than I have been alive and he dives with drysuit as primary bouyancy. I am not 100% devoted to any particular type/style of diving so I keep an open ear for when I come across problems. So far drysuit as primary has worked for me but if I come across issues with this style of diving I will be looking at changing to see if that solves the problems.

As mentioned by a lot of others before... don't do this, it's not wise!

 

[Subcooled]

I was taught to use my dry suit as my primary bouyancy control so closing the drysuit valve is mandatory. When doing left post shutdowns I was taught to use my right hand to close my dry suit exhaust valve and push it slightly out of the way of my forearm while simultaneously preforming the shutdown.

Disclaimer: I am strictly a sidemount diver. No rigid steel on my back, thanks!

There are two schools: those who want an automatic valve and those of us who want full manual control.

Personally, I do not want anything to be automatic.
-> It's either open or closed and the position of my arm makes all the difference if the valve is open.

The position of my arm is known to me but the amount of rotation of the exhaust valve remains a mystery unless its 0% or 100%

 

[Subcooled]

As you transition to diving doubles and more technical diving

Unless, of course, you want a more balanced experience as a sidemount trimix diver.

I’d suggest not using the drysuit as your primary inflation anymore. Having that much gas in your suit will eventually lead to a problem as you ascend from the deepest part of your dive to your first stop…just a suggestion.

The exact same amount of gas is needed in a wing for the same amount of buoyancy.
Hence, it all boils down to skill and also the efficiency of the dump valves.

Sure, a lot of air in the suit tends to move around a bit (how much weight do you carry?) and the dump valve is slow!
I tend to use both the suit and a wing. More gas in the suit makes you warmer.

 

[ELCAM]

Unless, of course, you want a more balanced experience as a sidemount trimix diver.



The exact same amount of gas is needed in a wing for the same amount of buoyancy.
Hence, it all boils down to skill and also the efficiency of the dump valves.

Sure, a lot of air in the suit tends to move around a bit (how much weight do you carry?) and the dump valve is slow!
I tend to use both the suit and a wing. More gas in the suit makes you warmer.

I think everybody uses both to some extent. The advice to the OP is too not just use the dry suit…as eventually a problem will arise in the ascent that could cascade into an incident/accident especially for a new tech diver.

Of course yes the same volume of gas is required in a dry suit as would be in a wing…but the wing is a much more compact place to keep that volume versus a giant bubble or multiple ones moving around your dry suit.