Drysuit Basics

[cottonbroker]

I was certified last year and have logged about 10 dives including a trip to Cozumel.

In my local lakes and Quarries the thermal cline is a major issue and I'm too cold in a six mil wet suit to go beneath about 20 ft.

I recently bought a Dry suit and want to start using that so I can get a little deeper.

Like anything else with diving I know it comes with risk so I want to ask about the basics that I will need to know and be aware of to dive safely in the suit.

Obviously Boyancy will be the main issue but I also want to know what the major issues that might happen and put the diver in a risky situation.

Thanks
Dave
Indiana

 

[reo]

I recommend you take a drysuit familiarization course. Your instructor will answer your questions, and point some things out that you may not have considered yet. Your instructor will show you what possible problems could arise, and how to deal with those issues.

Having a drysuit does give you more things to keep track of while diving, but it also makes the dive warmer and downright pleasant.

Good luck with your training.

Ron

 

[cldwdiver]

Great tip Reo,

And try to locate an experienced drysuit diver to buddy up with for a few dives.

A few "mentored" dives can go a long way towards improving your use of the drysuit.

 

[cottonbroker]

I appreciate the advice. I'm lucky because one of my two dive buddies is also my instructor and I plan on doing more dives with him soon. I just wanted to get some ideas about what to be aware of before he joined me so I wouldn't have a thousand questions for him and so we could spend a little more time diving and less time going over the basics that i could have been aware of already.

 

[TSandM]

Well, the issues with a dry suit are pretty easily seen, if you think about what they do and how they work.

First off, they are another air space to manage. Just like a BC, the air in the dry suit will compress and expand with depth changes. To keep neutral buoyancy, the suit will have to have air added on descent, and vented out on ascent. Unlike a BC, however, the dry suit generally only has one exhaust valve, so positioning yourself properly to allow venting is part of the skill of using the suit. Also because of this, being in a feet up position traps a lot of air in the suit that you can't vent, so procedures for recovering from a feet up position are part of a dry suit class.

Like a BC, the dry suit has an inflation hose and valve, both of which can malfunction. Procedures for recovering from a runaway inflator are important to know, which include disconnecting the inflator hose and dumping from your neck or wrist seals.

A dry suit can also leak or flood, and considerations of buoyancy loss when this occurs, as well as a proper choice of undergarments to cope with a lot of water in the suit, are part of the use of a dry suit.

Finally, the diver must make some choices about management of buoyancy -- How much of it will be done using the suit, and how much done using the BC. Different people recommend very different things in this regard (you can learn much from doing a search on dry suit and buoyancy here on SB -- There are many threads on the topic).

I think that kind of covers the basic idea of dry suit management, but I'm sure I've probably left something out that someone else will fill in for me.

 

[dannobee]

If you know nothing about drysuits, pick up a DUI or PADI booklet on diving dry. On the surface, they seem similar to a wetsuit, but there are buoyancy concerns (BCD for lift? Drysuit for lift?), weighting concerns, undergarment concerns, seal differences, etc., that the book will go over. I say this because giving advice to someone with relatively few dives is different than someone with say, 100 or 200 wetsuit dives who wants to go dry.

Your instructor will appreciate it if you have already read a booklet, especially with only 10 dives.

 

[Jack Hammer]

I think you'll find the drysuit class beneficial. I didn't think it would really make much difference, and in the pool it didn't seem much different than from a wetsuit to me. Once I got in OW it was a whole new diving experience. You'll likely have to spend a little time getting your trim and bouyancy control adjusted.

In my drysuit class I went to do a simple fin pivot, which I thought would be cake. I started it and I went feet up instantly. It took me 3 or 4 tries to not go upside down. I did 6 dives that weekend in the drysuit and played with my trim between each.

If I'd been on a boat dive with an instabuddy instead of with people who knew what they were doing, I could have had some real trouble. The last few dives went fine, but again I'm glad I took the class instead of just jumping in the lake and hoping to figure it out on my own as I went. (oh, and yes I had read the book several times prior and was aware of how to get out of an upside down position, but reading about it and pulling it off at 25' are two completely different beasts).

Jack

 

[nereas]

I was certified last year and have logged about 10 dives including a trip to Cozumel.

In my local lakes and Quarries the thermal cline is a major issue and I'm too cold in a six mil wet suit to go beneath about 20 ft.

I recently bought a Dry suit and want to start using that so I can get a little deeper.

Like anything else with diving I know it comes with risk so I want to ask about the basics that I will need to know and be aware of to dive safely in the suit.

Obviously Boyancy will be the main issue but I also want to know what the major issues that might happen and put the diver in a risky situation.

Thanks
Dave
Indiana

Taking a class will familiarize you with the suit, the buttons, and the dial settings, as well as practicing somersaults etc.

In the open water, you will normally bleed the suit of air first, then bleed your B/C, to descend.

During the descent, you will normally fill the suit first, to address suit squeeze (your gonads will be screaming if you do not), and use that as your descent speed control, until you get within sight of the bottom, at which time you will also fill the B/C as needed to stop your descent, after the suit is comfortable.

What you do during your bottom time varies depending on whom you talk to. I like to close my suit valve 1/4 turn. Some close it all the way. Others do not close it at all.

To ascend, you will normally open your suit's dump valve all the way, and dump air from it by shaking your arm, then ascend controlling the ascent speed with your B/C dump valve, combined with shaking air out of your suit with your arm as you go. It is a coordinated procedure that is tricky until you learn how to do it.

 

[on_two_wheels]

I don't dive dry but would highly recommend taking a dry suit specific class. Doing my first deep dive for AOW, the instructor allowed one of the other students to do her first dry dive at the same time. Needless to say, that was a bit much to tackle all at once and she had to share his air by the end of the dive. Honestly, it's a bit intimidating after seeing her troubles but I'll still do it sometime down the road.

 

[diverrobs]

I just got my drysuit in the spring and decided to do a couple of pool dive and a couple of open water dives. The biggest thing I found was that it is a lot more to manage. It is not a simple change from wetsuit to drysuit. I actually found the switch to drysuit more difficult than the open water or advance open water courses. Practicing in a pool is a really good idea. TSandM gave me alot of help through this Forum. Here are my recommendations (if you choose not to take a course) Note that there alot opinions on how to use a drysuit but this is what worked for me.

1) Only put the mimimum amount of air into the dry suit to get the "Squeeze" off. The drysuit will not vent air as fast as a BCD so if you start ascending it is easy to have a rapid ascent (I had a rapid ascent from 25' to 10' in my first OW dive with the dry suit, scared the hell out of me). Then use the BCD for bouyancy control.
2) Keep your dry suit valve all the way open once you begin to decend. This will help prevent rapid ascents. As you get better you may want to close it one quater to half a turn.
3) Practice moving the bubble around in the drysuit in the pool and practice recoving from a "Feet Up" situation. Way better to do this in the pool than in open water.
4) Practice venting air from the dry suit. Note that you can only vent air if the vent is where the bubble is. If your feet are up, no air will come out the valve. If you are ascending head first, you need to put your left arm up (with the valve up) to get the air our.
5) Practice task management in the pool. Ascending with a drysuit is one more thing to manage, you have to watch your ascent speed, vent your dry suit, vent your BCD(shoulder dump), keep track of your air and your buddy. I like to use my sholder dump for getting air out of the BCD and put my arm up and down to control venting from the drysuit. Takes practice to do this.
6) With the drysuit you are going to have alot more bouyancy than you have ever had. I am 170lbs and I need 26lbs of weight plus my HP100 steel tank to be neutrally bouyant. The added bouyancy means that at shallow depths, small changes in depth (2') result in big changes in overall bouyancy. Thus if you are at 20' and go up 2' your are going to have to vent air or if you go down 2' you are going to have to add air. Bouyancy control is way more of an issue (at least my experience in shallow water). The pool is great to practice this because the pool is shallow.
7) An instructor buddy of mine had me take off my BCD at the bottom of the pool to find out what happens when taking your BCD off underwater with a drysuit on (similar to what you have to do in the OW course). This is the scarriest thing I have ever done under water!!! Once my BCD was off, because of the added bouyancy, I headed for the surface and my BCD stayed on the bottom, it took me 15min. and 1500psi of air to figure out how to get the damn thing back on but I did it. DO NOT DO THIS WITHOUT SOMEONE SPOTTING YOU AND ON THE BOTTOM TO ASSIST YOU. This really is good practice if you have a problem in OW where you have to take your BCD off.
8) Practice your basic open water skills with the drysuit on and a buddy in the pool. Share air, buddy breath etc. This will help you learn more task management, it is harder with the drysuit.
9) Recognize in an emergency (i.e. while rapidly ascending) you can pull your neck seal and flood your drysuit to stop the ascent.

I did not appreciate how big the change was. I cannot say enough about the value a course would have been, it would have shortened the learning curve significantly. Having said that, after 3 pool dives and 3 OW dives with the drysuit, I think I got it down now. Practice Practice Practice. DO NOT go and do an OW dive without practicing with the drysuit, it is just too big of a change.

Sorry this is long but I though I would provide some insight given I just made the switch.