Drysuit Emergency

[jiveturkey]

I'm still fairly new to diving my drysuit so maybe someone who has experienced this can comment. I know in an emergency, you can vent air through your seals. But with latex seals, they're really tight and it's not so easy to get a grip with my thick gloves. Plus, my gloves come up over the seals on my arms and my hood covers the neck seal. I have enough trouble getting those things off on land. I can't imagine what it'd be like as I was shooting to the surface. I guess the neck would be easiest but it still might give me some trouble.

Any thoughts on this?

 

[Jim Lapenta]

What kind of seals do your gloves have. Are they a dryglove system or do they just come up over the seal(wetsuit gloves). What type of hood are you using. mine came with my suit and tho it comes over the seal it does not have an apron that comes down real far. For me to get to the seal I just have to unzip it. I did put a larger tab on the zipper just so I could get it easily with gloves. But I know what you mean about maybe not having time to do it. That's one of the reasons I took the drysuit course. Hopefullt what I learned about buoyancy and getting out of tight spots will be enough.One thing I did do at first was dive with wetgloves till I got comfortable with my suit. I've got like 20 dives on it and the biggest thing I do to minimize a runaway ascent is use the bc for buoyancy control and just enough air to take off the squeeze. I know that's not how it's taught but it works for me and alot of other people.

 

[Diver0001]

I'm still fairly new to diving my drysuit so maybe someone who has experienced this can comment. I know in an emergency, you can vent air through your seals. But with latex seals, they're really tight and it's not so easy to get a grip with my thick gloves. Plus, my gloves come up over the seals on my arms and my hood covers the neck seal. I have enough trouble getting those things off on land. I can't imagine what it'd be like as I was shooting to the surface. I guess the neck would be easiest but it still might give me some trouble.

Any thoughts on this?

Hey Greg,

With a few simple techniques you can deal with every possible problem without changing depth by more than a metre or two. In a good drysuit specialty you will learn how to have total control over the suit by (a) unclipping the inflator if need be (b) learning how to get prone from any imaginable position and (c) learning how to vent and maintain depth no matter what you're doing and/or what's happening (d) working a bit on perceptual awareness. Note that this is not a list of all of the skills and theory you will get, just the things that have to do with controlling the suit.

The basis for all of these skills is realising that no matter what, the suit can never fill faster than you can vent it. Also, the skills can be taught to most people in an hour or so of pool time if the instructor knows what he/she is doing. It's not difficult to learn but it's something that you might not stumble across on your own. Furthermore, if you're choosing an instructor for a drysuit specialty choose wisely. This is a specialty that really needs to be taught well or you'll come away wishing you had learned how to pull back your seals.... LOL

So why do people talk about pulling back the seals? The suggestion that you should learn to pull out the seals incase you are in an uncontrolled ascent is something you hear a lot but the percieved need for this skill is rooted in most cases in a feeling of anxiety/insecurity about not being in control. People who are in control of the suit don't think about the seals and people who think about the seals are probably not sure if they are in control.

Instructors (especially PADI instructors) will tell you about pealing back the seals because it's in the video. Why it's in the video is completely beyond me but there it is..... It's not the only thing about the PADI way that experienced drysuit divers disagree with but standards are what they are. A good instructor will tell you both what PADI says and why *and* the best practice.

R..

 

[jiveturkey]

I'm not worried about simply losing control due to user error so much as I am about problems that are beyond my control. And maybe that's me being over paranoid. I have about 12 dives in the suit and I feel in control...mostly. I'm not as confident as in a wetsuit but I think I"m doing ok. I'm still playing with closing and opening vents and trying to tweak my skills.

I worry about not thinking as quickly. I've been diving wet for about 4 years so things are pretty much second nature. With the drysuit, I have to stop and think about every move I make. I probably need more experience before I just do things naturally without having to think about them. Maybe then I'll be less worried about catastrophic failure.

 

[Doc Intrepid]

Greg,

Diving a drysuit is primarily about ensuring that an emergency doesn't happen to begin with. I refer not so much to a slow leak in an LP hose, which can be disconnected, but to the awareness of the diver to trim, bouyancy, and effects of changes in depth.

I have the utmost respect for Diver0001's experience vis a vis 'not filling faster than able to vent', but in my experience it is indeed the case that - once an uncontrolled ascent begins - the gas inside the suit can and will indeed expand faster than the ability of the valve to exhaust that gas, particularly at only 2-3 ATAs. The undergarment gets in the way, plus the diver is already ascending, moving around (arms and legs), and changing position in the water column.

I second Diver0001's suggestion that you consider a class - they often spend quite a bit of time on the "tuck into a ball and roll 180 degrees" to reverse a feet-first ascent, and other techniques to respond to issues commonly experienced by some new drysuit divers.

But due to the design of drysuits - notably they have arms and legs - they will never vent or exhaust with the speed and thoroughness of a wing or BC bladder. This is the foundation of the argument for using your drysuit for thermal protection, and your wing for bouyancy control - you want to keep only a minimum of gas in that drysuit; not use it as a BC. (And I'm not aware of a single case where a diver, rocketing upwards in an uncontrolled ascent, had either the time or the mental awareness to successfully yank a glove off and crack a seal before they were already passing through 30' on their way to the surface...)

Body positioning or trim in the water is important (exhaust valve at a high point), keeping a minimum of gas in the drysuit is important, and situational awareness is very important. Drysuits demand a higher level of attention than wetsuits especially during the ascent, in my humble opinion.

The best way to deal with uncontrolled ascents in drysuits is to prevent them before they occur, because once they get going, stopping an uncontrolled ascent is challenging at best.

If you stay aware of it, your comfort level will increase dramatically over time.

JMHO. YMMV.

 

[TSandM]

I second everything Doc Intrepid said. Having been the victim of two uncontrolled ascents, one related to my improper management of an air-trapping undergarment and one to a sticking drysuit exhaust valve, I can say that I did not have time to think of unzipping my hood or ripping a glove off (easier said than done with my heavy neoprene gloves) to reach a seal. I would have been on the surface before either was accomplished.

The secret to a drysuit, as far as I can tell, is anticipation -- stay well ahead of what's happening with your buoyancy, which means staying VERY aware of your depth and in particular, your rate of change of depth. I have found this much easier if I minimize the air in the suit and use my BC for buoyancy. The BC has more than one place to dump air, depending on the posture I have in the water at the time, and if one fails, I've still got another. In my opinion, that is not true in a practical sense with the drysuit.

My PADI instructor strongly disagrees with me, feeling that managing one air bubble is far less complex than managing two, so there are differences of opinion on this subject.

 

[Diver0001]

I have the utmost respect for Diver0001's experience vis a vis 'not filling faster than able to vent', but in my experience it is indeed the case that - once an uncontrolled ascent begins - the gas inside the suit can and will indeed expand faster than the ability of the valve to exhaust that gas, particularly at only 2-3 ATAs. The undergarment gets in the way, plus the diver is already ascending, moving around (arms and legs), and changing position in the water column.

I think I need to qualify this remark. I was making the assumption that you weren't already in an uncontrolled ascent. What I was thinking when I wrote that is that a free-flowing inflator can't cause an uncontrolled ascent (if you know what you're doing) because modern suits can simply vent faster than the inflator can inflate.

One of the things I make students do when I assist with drysuit specialties is this: once we introduce all the skills and drill them, I will "sneek up" on them fom behind and hold the inflator button in while I push their legs up. Most students are able to disengage the inflator while rolling out of it and venting the suit without changing depth by more than two metres.

Uncontrolled ascents are a different animal than what I was thinking about. On the one hand they are *all* about diver error and therefore completely avoidable and on the other hand, once you're in one it may be impossible to get it back under control. In that sense I totally agree with Doc when he says "diving a drysuit is primarily about ensuring that an emergency doesn't happen to begin with".

R..

 

[Diver0001]

My PADI instructor strongly disagrees with me, feeling that managing one air bubble is far less complex than managing two, so there are differences of opinion on this subject.

For what it's worth, Lynne, I agree with you on the whole. If having two air-bubbles is too much for someone to fathom then having one monster of an air bubble floating all the way from your neck to your ankles is going to be a nightmare. Having said that, there's maybe more to it than meets the eye.....

While I understand why PADI suggest this (minimize task loading) I actually think that putting all the air in the suit is generally counter-productive. It creates an unnecessary problem (dynamic instability) while solving none. Moreover, the dynamic bubble can create more task loading (how to get it all to the vent; how to keep feet down; etc) than keeping the bubble small (albeit split) and under control..... and finally, having some easily-dumped air in the BCD can actually help beginners because failure to anticipate (which in my mind is the root of all diver error....hence attention for situational awareness in a drysuit specialty) can be compensated to some extent with a quick dump of air from the BCD.

In addition, your trim can be affected by where you put the bubble. I had a student once (I was assisting) who, for the life of him, couldn't keep his feet down. His instructor told me that he wanted to put him in ankle weights but I have an allergy for ankle weights so I offered an alternative. He was wearing a fairly loose fitting trilam suit with integrated weights. So I put him in a weightbelt, got him to pull all the "extra" material from the suit over the weightbelt and put proportionally more air in the suit than the BCD.....and presto. He looked like he was hung from a silken thread. After the dive his feedback was almost poetic....I love these moments; I felt *so* proud.

There is a lot to be said about drysuit diving. Exclusively using the suit for buoyancy is ridiculous but as you can see from the previous example, using the suit only for squeeze is also a gross over-simplification. The point is more subtle. You have options. You need to understand what these options win you and what they don't.

R..

 

[jiveturkey]

So what I'm hearing here seems to be that venting through the seals isn't really a viable option. It's more about control and recognizing the problem before it becomes out of control. I guess the chance of having my vents fail at the same time as a stuck inflator would be pretty rare.

How common is it to have an inflator stick? Why did that happen to you TSandM? Did it freeze?

 

[Diver0001]

So what I'm hearing here seems to be that venting through the seals isn't really a viable option.

No. You're hearing that if you have your suit under control it's the last thing you should *need* to do......As TSandM said, it's all about anticipation.

Inflator "freeflows" conform the image they give you of massive amounts of air filling your suit are extremely rare. Even such a free-flow is easily dealt with but most are much more subtle.

Most "free-flows" are hardly perceptible. You'll be diving along and you will realise that you have to continually dump small amounts of air even if you aren't changing depth. In this case simple unclipping the inflator is enough.

You can also "hear" when an inflator valve is sticking.....I'm about to try describing the difference on the internet for the first time ever that I"m aware of.....

Assuming a quick press of a valve that works normally, the sound it makes is this:

PTSHHHTTT

A valve that's likely to freeflow will sound like this:

PTSHHHTTTSHHHhhhhh...

Whereby you lifted your finger at the point where you see the highlight.

Sometimes a valve will make this sound for many dives before it really starts to misbehave. As an experienced drysuit diver you'll be able to see this problem coming a mile away.

The problem Lynne had with a vent sticking is also very rare. I've seen them get plugged with a poor choice of undergarment but sticking is rare. Also, modern vents can be manually activated by pressing them if such a problem does occur. It makes the ascent a little slower but it's hard to imagine a valve that gets so screwed up that it doesn't work at all.... with all due respect to Lynne, I feel that this probably could have been avoided.

R..