Drysuit Insight

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Scubaliz

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Hey everyone,
I have a question about drysuits.. I live in San Diego, and coming from the East coast, the water is way too cold for me to comfortably dive regularly (even summer nights usually) without a drysuit. Let's just say the thermocline kicks my ***.

That being said, I took my drysuit certification class (PADI) and was taught-- as the books even say, NOT to use my BC for inflation with my drysuit-- to solely use my drysuit. I found this to be ridiculous and I was constantly floundering around with about a two foot bouyancy difference with every breath. I am a very small person, so of course, the rental suit was insanely large and I had a lot of room for air to be trapped in spaces. This made the suit very uncomfortable (squeezes with wrinkles suck!) and hard to manage during any inflation. Unfortunately, I can't afford to buy a drysuit, so I have to deal with big suits for a while. I had much too much weight on, so I was having to compensate with air in my suit, and then had the misfortune of losing a weight pocket (damn the first generation velcro!!) at about 80 feet, suit extremely inflated for the depth... Needless to say, had I not practiced the skills of "kick down for your life or die" I would have had a marvelous runaway ascent on my hands.
I was able to kick down and grab onto my buddy, who could see by the fear in my eyes that something was really wrong. I pointed to my weights laying on the ocean floor and we ended up spending about ten minutes trying to get the pocket back in... which, had I had on videotape, would have made an awesome addition to any drysuit class... I ended up having to take off my BC entirely and replacing the pocket. Do they even make those stupid velcro things any more???
My question is this... I learned from various instructors that while diving dry, one should keep A) the valves always closed, or B) the valves always open and C)use the suit for inflation or D) use the BC for inflation. I am thoroughly confused, and as a result am wary of diving dry because I have no idea what would be the best ways to avoid dangerous situations that are bouyancy related. I have used a dryusit about ten times and still feel uncomfortable and a bit floppy and out of control in the water. What do you think?
 
This gets debated here from time to time, and there are clearly two schools of thought about it. I was taught (PADI) to use the suit for buoyancy. Like you, I found that hard to manage. I decided for myself to use the BC and minimize air in the suit, and later was taught by another agency that that was the correct approach. It works better for me -- air stays a lot closer to my inflator/dump than the air in my legs is to my dry suit valve, so I can vent a lot faster from the wing.

I haven't seen a discussion of valve open/valve closed, but I leave mine open all the way, all the time. I've never had any problem with it venting when I don't intend to, but leaving it open means I can vent quickly if I do want to.

From my admittedly limited experience, diving in a dry suit is much more difficult than diving in a wetsuit. Every time I've had a chance to dive wet, I've felt as though my competence had taken a leap upward -- every time I come home, I find out it's not true:)
 
Drysuits keep you dry and Bouyancy Compensators compensate for Buoyancy changes.

Controlling your buoyancy with a drysuit is extremely difficult and leaves you with huge dynamic instability (the bubble moves all over the place as you change position). I still don't understand whay the agencies teach it that way.

I leave the valve all the way open, dive "shrink-wrapped", and use the BC for buoyancy. Air you don't have in the suit can't send you rocketing to the surface.

The only air in my suit is just enough to keep the suit-squeeze to about what you would get with a wetsuit and loft up the underwear.

Terry


Scubaliz:
Hey everyone,
That being said, I took my drysuit certification class (PADI) and was taught-- as the books even say, NOT to use my BC for inflation with my drysuit-- to solely use my drysuit. I found this to be ridiculous and I was constantly floundering around with about a two foot bouyancy difference with every breath. I am a very small person, so of course, the rental suit was insanely large and I had a lot of room for air to be trapped in spaces. This made the suit very uncomfortable (squeezes with wrinkles suck!) and hard to manage during any inflation. Unfortunately, I can't afford to buy a drysuit, so I have to deal with big suits for a while. I had much too much weight on, so I was having to compensate with air in my suit, and then had the misfortune of losing a weight pocket (damn the first generation velcro!!) at about 80 feet, suit extremely inflated for the depth... Needless to say, had I not practiced the skills of "kick down for your life or die" I would have had a marvelous runaway ascent on my hands.
I was able to kick down and grab onto my buddy, who could see by the fear in my eyes that something was really wrong. I pointed to my weights laying on the ocean floor and we ended up spending about ten minutes trying to get the pocket back in... which, had I had on videotape, would have made an awesome addition to any drysuit class... I ended up having to take off my BC entirely and replacing the pocket. Do they even make those stupid velcro things any more???
My question is this... I learned from various instructors that while diving dry, one should keep A) the valves always closed, or B) the valves always open and C)use the suit for inflation or D) use the BC for inflation. I am thoroughly confused, and as a result am wary of diving dry because I have no idea what would be the best ways to avoid dangerous situations that are bouyancy related. I have used a dryusit about ten times and still feel uncomfortable and a bit floppy and out of control in the water. What do you think?
 
Scubaliz:
My question is this... I learned from various instructors that while diving dry, one should keep A) the valves always closed, or B) the valves always open and C)use the suit for inflation or D) use the BC for inflation. I am thoroughly confused, and as a result am wary of diving dry because I have no idea what would be the best ways to avoid dangerous situations that are bouyancy related. What do you think?
Liz,

(oops, Terry was faster...)

As with most items of dive gear, fit is critically important. Drysuits that fit make it much easier to dive dry. One suggestion is to monitor this website:
http://www.dui-online.com/fr.htm
(where it says "for list click here" at the bottom)

You've noted that you're small. On this site are frequently real small suits (most drysuits are pretty 'unisex') that are sold at a discount for one reason or another. These are generally new suits. If you can find one that is in your size, you win...

As for the rest, I've been diving dry since 1986. I don't own a wetsuit. What follows is my opinion, but its a reasonably informed opinion:

(To address your questions basically in order; )

* Dive with the valve always open. Drysuits are not like BCs...they don't 'dump' well. This is because, in part, they have arms and legs. The valve isn't always at the highest point. Therefore if you need to dump gas quickly to avoid an ascent, you cannot always exhaust the gas more quickly than its expanding due to the diver's ascent. This situation is compounded if you close the valve. So in a drysuit its important to 'stay ahead' of any need to dump gas during the ascent - it's important to maintain control during your ascent. You do that by keeping the valve open and making sure its (close to) the highest point, so the suit will automatically exhaust gas during the (slow, controlled) ascent. (Sometimes after the dive is over divers may close the valve and inflate their suits with argon to warm up, but during the dive the valve should be fully open.)

* Your trim in the water during a dive is variable. Gas in the drysuit always seeks the highest point. Your goal in precision diving is to control your bouyancy and trim. If you have too much gas in your drysuit and your trim changes, that gas in your drysuit commences to shift around in the suit from torso to feet or vice versa, as the gas seeks the highest point. Aside from it feeling a bit like gerbils are running up and down your legs, the consequence is that its much harder to control your trim precisely with the gas constantly shifting around in your suit. To avoid the constant feeling of instability and needing to "regain your balance", dive with the least amount of gas in your suit (necessary to prevent suit squeeze). This minimizes the amount of gas that can shift around inside your drysuit as your trim changes during your dives.

Your drysuit is an efficient and effective means of providing thermal protection against cold water. That is what its designed to do.

Your bouyancy compensator is designed to effectively provide equilibrium - or neutral bouyancy - no matter what depth you are at. Thats what its designed to do.

One reason why new drysuit divers are taught to use their drysuits as BCs (which is sort of like using a flashlight to drive nails...can be done, but not optimal) is because it is generally felt that to have TWO separate gas-filled bladders is too complex for new divers. You halve the complexity if you only give them one gas-filled bladder to contend with - ergo, they're taught to leave the BC empty and only use the drysuit.

Which creates all sorts of disasters, but by god, it cuts the complexity by 50%...

Learn to dive using your equipment as it was designed. Use your drysuit to provide thermal protection. Use your BC or wing to provide neutral bouyancy. Yes, its more complex. You now must monitor and control two gas-filled bladders during your ascents (and descents). But it isn't rocket science, and like rubbing your stomach while patting yourself on the head simultaneously, most divers are capable of learning how to dive with the additional complexity.

Hope this clears up some of your confusion,

Doc
 
So far it seems everybody here does not do it the padi way. I was taught what everybody else is doing, i.e. use the BC for it's intended purpose and the drysuit for it's purpose. Leave the valve wide open and you're good to go.

I did it the padi way in the beginning and it was not as easy as it sounded, I think that's why there's a lot of problems with new padi drysuit divers...
 
I have a grand total of 3 dives dry, but tried it the PADI way for about 10 min and figured out that this was dumb for all the reasons quoted. Yes it is a little more complex to manage two bladders, but way simpler to keep the dry suit with enough air to keep warm and use the BC as I always have. A little tricky on the ascent but with the valve open as long as it is at the top it pretty much manages itself.

Trying to manage boyancy with the drysuit had my trim all over the place. Tried it out in a "jungle gym" and figured out pretty quickly that this was just not going to work. The air "bubble" is just way too mobile on your body. Both PADI instructors I went with told me to use the BC notwithstanding what is in the manual.

I think if you were very new to diving and diving dry for the first time it might be too many things to manage, but that is the only time it would make any sense to me.

Just my 2 cents.
 
cummings66:
I did it the padi way in the beginning and it was not as easy as it sounded, I think that's why there's a lot of problems with new padi drysuit divers...
Thats usually because most people are overweighted (Especially when using a drysuit for the first time). A properly weighted rec diver using a drysuit and a Alum 80 shouldn't have much issue using a drysuit to control buoyancy. The real problem with the technique is after you leave that situation (>80 ft3 of gas), the air bubble gets bigger and more unmanageable.
 
But your answer was much better :cool:

Terry


Doc Intrepid:
Liz,

(oops, Terry was faster...)

As with most items of dive gear, fit is critically important. Drysuits that fit make it much easier to dive dry. One suggestion is to monitor this website:
http://www.dui-online.com/fr.htm
(where it says "for list click here" at the bottom)
 
ScubaLiz,
The lady who owns the dive shop with which I'm affiliated is a PADI instructor. She teaches the course by the PADI standards but dives the opposite.

I think the underlying concept PADI has is that if one uses the D/S for buoyancy compensation, then the diver has but one buoyancy device with which to contend during the dive (reduction of task loading).

I'm very, very new to D/S diving, but, like others, have found that it's much easier to use the D/S only to offset suit squeeze and use the B/C for its intended purpose.

the K
 
Thanks everyone, I feel better now that I can go with my gut with less worry-- I'll let you know how it turns out...Liz
 
https://www.shearwater.com/products/teric/

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