Twins with only drysuit for buoyancy

[DaleC]

I usually leave my vent fully open. It vents automatically. Even when I might shut it for some reason, when I want to ascend or change depths, I open it and it vents automatically from that point on. Sometimes I need to raise my shoulder a bit (I have a shoulder dump valve) to get the air out but it doesn't require my hands.

Yes, that is how I usually dive too (fully open). If I'm at a constant depth I'll close it and take some of the squeeze off "I like a little squeeze" but once I've vented to correct bouyancy (say on ascent to a safety stop) I still have to close the valve to stay there or I will lose too much air and begin descending. It sounds like Lynne is saying she can vent and stop venting without using her hands. Maybe I'm not reading her right.

 

[DaleC]

Somehow I managed to buy a dry suit without Putting Another Dollar In. I read the PADI instructions and also did a little research on the subject. In the end, I decided that I needed to know how to use the dry suit for buoyancy in case of a wing failure, so I spent the Summer using my wing and my suit for buoyancy control on alternate diving trips. I dive steel singles, and have had no problem using the suit, although I admit that since I am self-taught, I may be Doing It Wrong.

That being said, my thought is to use the wing for buoyancy and just keep the squeeze off now that I have some (possibly misplaced) confidence with the suit. And obviously, that's all I get when diving wet down South.

I don't think you missed much on that course I'm afraid. It was worth it for me I guess as I bought a used suit with oversized boots and nearly killed myself doing loop de loops for 45 minutes trying to recover from the head down position.
As far as putting another dollar in goes; I am cringing at the $ I just paid for my EFR prerequisite to RD. I almost want to whack someone just so I can get my monies worth by reviving them.
Too bad we weren't closer. We could probably drink some Kool aid together

 

[D_B]

Somehow I managed to buy a dry suit without Putting Another Dollar In. I read the PADI instructions and also did a little research on the subject. In the end, I decided that I needed to know how to use the dry suit for buoyancy in case of a wing failure, so I spent the Summer using my wing and my suit for buoyancy control on alternate diving trips. I dive steel singles, and have had no problem using the suit, although I admit that since I am self-taught, I may be Doing It Wrong.

That being said, my thought is to use the wing for buoyancy and just keep the squeeze off now that I have some (possibly misplaced) confidence with the suit. And obviously, that's all I get when diving wet down South.

I don't think you missed much on that course I'm afraid. It was worth it for me I guess as I bought a used suit with oversized boots and nearly killed myself doing loop de loops for 45 minutes trying to recover from the head down position.
As far as putting another dollar in goes; I am cringing at the $ I just paid for my EFR prerequisite to RD. I almost want to whack someone just so I can get my monies worth by reviving them.
Too bad we weren't closer. We could probably drink some Kool aid together

I got much more out of my drysuit course I guess then most, I never would have known how fast things can go south and how imortant it was to practice, without taking it

 

[drdaddy]

The PADI drysuit course teaches the diver to use the drysuit to control buoyancy and the BCD to keep the diver afloat at the surface.

When using an AL80 (or any smallish tank) and having the diver weighted right, the excess gas bubble is not so large. (and thereby easier to manage.)

JeffG is correct about the official PADI position - Read this:

... At this point, stop using your BCD for buoyancy ocntrol and use primarily your dry suit. Use your BCD at the surface, or in case of emergency. To attain and maintain neutral buoyancy underwater, add to and release air from your dry suit. ..."
PADI - Adventures in Diving Manual, 2005, page 156

You all may have different opinions and styles and procedures, but this is what PADI's position is.

drdaddy

 

[Dive Junky]

I dive with a single steel 120 and have never had a problem using my drysuit only for buoyancy. In fact I prefer it. Once the dump valve is dialed in to the right spot you never have to touch it again. Do it right and its hands free buoyancy for the entire dive unless of course you need to add a little air. No way around that one.

 

[Dive Junky]

JeffG is correct about the official PADI position - Read this:

... At this point, stop using your BCD for buoyancy ocntrol and use primarily your dry suit. Use your BCD at the surface, or in case of emergency. To attain and maintain neutral buoyancy underwater, add to and release air from your dry suit. ..."
PADI - Adventures in Diving Manual, 2005, page 156

You all may have different opinions and styles and procedures, but this is what PADI's position is.

drdaddy

Pinnacle drysuit user manuels say the same thing.

 

[DaleC]

Well, thanks a lot! You had me running around looking for my PADI books

Even though I took the course I don't like diving that way. They talk about the air being distibuted uniformly but IME it doesn't work out that way. It either wants to travel up or down and I have to work harder to maintain trim. Using minimal air in the DS with more in the BC keeps the bouyancy bubble on my back and the pivot point in one spot.

They also talk about two main benefits: Not switching between two bouyancy sources
and not experiencing suit squeeze. The first is a non starter for me because I don't find using my BC and DS during a dive to be overly stressful. I tap on the DS to take off the squeeze and adjust bouyancy with the BC. I guess that takes care of #2 as well. Bear in mind I like a slight squeeze as opposed to a loose DS.

One big issue they don't touch on is dealing with a runaway ascent. If you have a big bubble in the suit and you find yourself ascending too quickly the valve might not be able to vent quick enough - result, burping the neck seal and possible flooding. I haven't had that problem but I have seen others flood just that way.
With a smaller bubble in the DS the valve can keep up and the BC can dump air far faster than the DS.

All this is just my experience and I'm not disagreeing with PADI, I keep spending money there. It's their agency and they can make their rules any way they want but, I have to admit... I don't wear a snorkel on my mask either :shocked2:

 

[JeffG]

Pinnacle drysuit user manuels say the same thing.

and the DUI one as well.

 

[TSandM]

Under these conditons you waste so much gas venting the drysuit and blowing it back up, then venting again.

Since I can do two deep dives off a 6 cubic foot Argon bottle, I'm not really worried about the volume of gas that I'm using for suit buoyancy, even with a up-and-down profile. It's never made any significant changes in my calculated SAC rate.

I keep my drysuit valve open all the time. When I want gas to stay in the suit, I keep my left arm a little down. If I want to vent, I just raise the elbow. If the arm is in precisely the right position, the suit will vent itself automatically as I go up. It's quite nice to have my hands free when reeling out.

 

[DaleC]

I keep my drysuit valve open all the time. When I want gas to stay in the suit, I keep my left arm a little down. If I want to vent, I just raise the elbow. If the arm is in precisely the right position, the suit will vent itself automatically as I go up. It's quite nice to have my hands free when reeling out.

Thanks Lynne, that's what I was wondering about.