Dry Suit Need Tips

[furby076]

So I tried my dry suit for the first time yesterday at dutch. To say the least it is a hell of a lot harder then I thought it would be. Had the dive instructor with me, and I am having a hard time getting it down (admittedly only two dives).

NOTE: In a wetsuit I am impressive when it comes to buoyancy. I picked up my buoyancy skills by my 3-4th dive. It's easy for me. It took me all of ten minutes to realize how to keep my buoyancy, while facing towards the sky, and using my dive camera.

So I know I don't like ankle weights, kills my trim, and make me less balanced.

I figure for now I will use my BC to control my buoyancy, but need help with the dry suit. I am definitely getting a squeeze on it, and am filling it with air (short bursts). Is there a time I should be filling it with air and times where I shouldn't? Should I put air on the surface, and not touch it from there? I would think that is not a good idea since compression means I get less air between me and the water, and then get cold.

I know the fine-tune balance will come with time, but I had about 4-5 uncontrolled ascents....two of those from 90 feet (I am lucky I didn't get bent). No I didn't plan to go to 90 feet. I was swimming and all of a sudden starting flying up. I started venting air from the dry suit AND BC at the same time...hit the surface, and dropped like a rock (hence I got to 90 feet).

Eventually my air pressure went to 100 PSI, and I swapped to my pony.

Yea this was not a fun dive, but I am sure it will come with more time...but in the mean time any tips/techniques/etc?

 

[hypertech]

Number one, do not go to 90 feet as a new drysuit diver. I can't believe your instructor would have you do that. Stay around twenty feet till you have yourself sorted out. Ideally you can dive somewhere with a soft bottom so this won't happen again. I just don't see how even as a new diver you could gave such an uncontrolled ascent followed by such a descent and another uncontrolled ascent if your instructor had prepared you adequately. And if he did and that happened he should have debriefed with you right then to answer these questions and not have you turning to the Internet to sort it out.

Number two, get a new instructor. See number one.

Number three, remember your gas management no matter what you are diving. You should not be getting down to 100 psi on any dive.

 

[jwin]

OMG! :shocked2:
This guy needs help!!!

 

[tbone1004]

wow.... just wow...
yeah, so clearly your instructor has issues if he hasn't addressed the two main buoyancy thoughts with drysuits.
No mention of burping it clearly since you mentioned filling at the surface.
Your use of air in the suit depends on how cold you are at the time and your dive time, if you're on deco, and a myriad of other things. Colder, on decompression, long dives times, I use more air in the suit. For quick short things I keep a squeeze.

How in God's name did you have an uncontrolled ascent from 90 feet? The drysuit can vent air a LOT faster than that... You had to have been diving WAY too heavy to have enough air in the bc and suit to cause you to go up that fast. With a drysuit the buoyancy doesn't change for the most part, and you clearly weren't diving doubles. So you're buoyancy swing couldn't have been more than 10lbs from start to finish. Just saw another post where a guy had 16lbs of lead on a trilam drysuit with a SS plate and a LP95.
I'm thinkin you were in a similar boat and had way too much air in that bc and suit, didn't have the exhaust valve open all the way, etc etc. One thing to do if you end up in an uncontrolled ascent like that, is to make sure you exhale all the way, and you can crack a wrist or neck seal to vent the rest out real fast. Your dry dive will become wet, but wet beats bent anyday.

good luck...

 

[Rand]

You probably should discuss your concerns with your instructor as I don't think they fulfilled their obligation to you if you had such a wild and dangerous first couple of dives in the suit and left the dive site with unanswered questions.

After that, I would suggest doing a good weight check as it appears, as others have said, that you were overweighted. Grab a buddy, gear up in your drysuit and undergarments, but no scuba kit. Make sure you purge the air from your suit on land by squatting while pulling the neck seal slightly away from your neck as you squat. Have your buddy help get all the air pockets out. You should feel pretty shrink wrapped at this point. Put on your hood, and gloves.

Grab your weight belt with your best guess of weight requirements (I like to use a weight belt with pockets to insert weights rather than thread them on a belt--it saves time), spare weights in 1-2 lb increments, and your buddy and walk into the water (again just wearing your drysuit with undergarments, gloves and hood) and figure out exactly what it takes to sink you in your suit. Add or subtract weight until you can sink yourself.

Now, repeat this step with all undergarments you may have, as heavier or lighter undergarments will mean different weight requirements.

With your suit buoyancy now known, think about the buoyancy characteristics of the rest of your gear. If you have a BP/W, this is easy. Traditional BCDs might take some figuring out and testing, much like you did for your suit as many have inherent positive buoyancy even empty.

Remember to account for buoyancy shifts in your tank if applicable.

Add up all your negative buoyancy values such as regs (1-2 lbs) and subtract that from the lead needed to sink you in the suit, again taking into account tank buoyancy if applicable. This should be the weight you need if you did all your checks and math correctly.

Take the suit out on a couple dives to test it out.

As far as diving the suit, you always start with all the air purged from it. I use my BC for buoyancy and add a little air to my suit as needed to make the squeeze just tolerable, keeping just the bare minimum amount of air in it. My exhaust valve on the suit is always fully open.

As you descend, you are going to have to add more air to the suit to counteract the squeeze. As you ascend, you need to anticipate venting the suit early and often as the suit valve does not vent as quickly as your BC valve will. My valve is on my left arm, just above the elbow. I make a chicken wing with it as I vent it, with my fist touching my chest. This keeps air from pooling by my wrist in the arm with the vent on it. I rotate slightly making the vent the highest point when I vent air from the suit.

You really want to make sure you keep up with venting the suit, keeping just the minimum amount of air to make the squeeze tolerable. This is especially as you reach the last 30 feet or so as this is where you will experience the largest expansion of the air in the suit. You should have almost no air in the suit before reaching 30 feet.

It may help you to ascend keeping in contact with a vertical rope from an anchored buoy the first couple of times as you get used to venting the suit. This will give you something to grab on to should you start to ascend faster than you can vent.

Ideally, you want to create what has been described as a sort of tripod when trimming out. You should have an air bubble over your back and a bit of air in each ankle to keep your feet a bit floaty, but not so much that you invert. This takes practice to get to know the feel of how much is enough. This posture works great with frog kicks.

It does take time to get used to diving a drysuit. For me, it was something like 20-25 dives in it. I still need to knock the cobwebs out of my head when I use it for the first time each season or switch back to it from an extended time diving wet. 1 or 2 dives in it and it all comes back.

Keep practicing with it and you'll get it.

 

[furby076]

Thanks for the tips folks. I will take this in and recalc my weights. I think that may have been a big issue.

On a side note, I did spend the dive before on the platform and felt "OK", not great, but I chalked that up to inexperience. The dive should have been relatively uneventful, but we go to the quarry to learn (thank god this wasn't off the Jersey coast).

The planned dive was to about 60 feet - I say about because we were doing navigation, search/recovery so the exact depth was not provided, but it was in that range.
The instructor was fine - not his fault, and actually managed to grab my ankle and ensure I didn't pop up a gain and get bent.

Hopefully in the next few weeks I will get a chance to try it out again...though unfortunately I will not be diving dry on my next boat trip as I am not ready for that.

Thanks again!

 

[furby076]

My exhaust valve on the suit is always fully open.

Thanks for all the tips, I will print and try these out. Quick question about what I quoted. You said fully open. Is this ALWAYS the case? Anytime not to have it fully open? I was told to have it fully open with three 1/2 twists closed (roughly).

I have the BARE suit and the valve is between my upper arm and elbow, but closer to the joint of the upper arm.

I forget, what's the general recommended weighting calculation?

Good thing I didn't take my camera rig lol.

 

[FWADIVER]

I keep mine closed 2 clicks to keep a 10ft squeeze. Depends on the exhaust valve, I find the apeks 3 clicks is about the same as 1 click on the sitechs but ymmv. If you are overweighted you might need to close it more to keep enough air in your suit to float.

 

[TSandM]

There are two basic approaches to using a dry suit with a standard, single tank recreational setup. One is to use the suit for all your buoyancy compensation needs, and only use your BC at the surface. The other is to put enough air in the suit to allow mobility and allow your undergarments to function uncompressed, and use the BC for any other compensation.

A dry suit should be empty at the surface. It will be, unless you have closed the valve, because if you are floating in a vertical position, your legs and torso will be squeezed and the air will come out the exhaust valve. As you descend, you add air to stay close to neutral. If you are overweighted, you will not be able to keep the air you need in the suit without partially or completely closing the valve -- assuming you are in a horizontal position, the need to close the valve should be a clue to correct your weighting.

Uncontrolled ascents in a dry suit are very dangerous, because most suits have only ONE venting site, and the valve does not vent as fast as the inflator on a BC does. If you get beyond a certain degree of overexpansion, it may not be possible to get the air out of the suit fast enough to stop yourself, unless you can get a finger under your neck seal and open it (which will make you wet, but no longer buoyant). I don't know what the temperatures in Dutch Springs are, but in Puget Sound, by the time I dug through the warm collar on my suit and the neck portion of my hood, I'd be on the surface before I got to the seal.

Anticipation is important in any buoyancy control, but with dry suits, anticipation and position in the water (trim) are downright crucial. If you are too vertical, you may not be able to keep air in the suit. If you are too much head down, it will be difficult to impossible to vent the suit. And if the suit gets too much away from you, you are toast.

 

[Bubbletrubble]

• What kind of instructor would take a diver on his first dive ever in a drysuit to a depth of 90 ffw?
• After a student had an uncontrolled ascent from 90 ffw, why would the instructor allow him to conduct another dive to the same depth? (OP reports having two uncontrolled ascents from 90 ffw.)
• If the planned dive was to a max depth of 60 ffw, why wasn't that parameter respected?
• How could an instructor allow a student to get into a low-on-air (100 psi) situation (assuming no regulator malfunction, massive reg hose leak, etc.)?

The OP needs to select a new instructor who is an experienced drysuit diver and exercises better judgment.

@furby076: Did you have a shallow pool session in your drysuit prior to diving at Dutch? If so, then it would have been appropriate for the instructor to discuss proper weighting, emergency techniques (feet-first ascents, stuck inflater, etc.), and the subtleties of managing the bubble inside the suit at that time.

FWIW, there is no "calculation" that is accurate for determining appropriate weighting.
You simply have to conduct a proper weight check.