How many dives to get comfortable with your drysuit?

[Doppler]

If it fits, you should be starting to get the hang of it after a handful of dives. If it does not fit, you may always be fighting with it.

A good way to work on the simple skills you'll need, is to find a sheltered, shallow spot and practice controlled descents and ascents... move from eight or nine metres to around two or three and then go back down again, trying to stop before you head for the surface or bounce off the bottom. Do this in water no deeper than 10 metres. Have a buddy with you.

Make sure the dump valve works well and that your thermal undies "release" gas rather than trapping it. Also, add only enough gas to make yourself comfy, and make any adjustments slowly.

Have fun.

 

[James R]

What Doppler says above is spot-on in my experience.

I've had my drysuit a while, going on my 3rd season with it. I hate it, though not because I have trouble diving it, but simply because it's too big and too short at the same time so I have limited mobility in the shoulders (ie reaching my valves is a real struggle) yet there's way too much material everywhere else. I only put enough gas in the suit to prevent squeeze and a tad more, and use my wing if I need a bit more lift at depth.

When I do the DUI demo as a dive leader, however, it's fantastic to dive dry in a suit that fits! If only they had pee valves in their demo suits

 

[FinnMom]

Quite a few, like maybe 50 to feel like I was back to the same bouyancy control I had had w/ a wetsuit. It's a bit help to remember that if you are practising shallow, exactly the shallow depths (18' or less) are exceptionally challenging.
Try to stay horizontal so your body is at one depth, not a nearly 6' range of depths. Leg wraps can be nice, esp. if the suit is a bit roomier than necessary and most esp. if the boots are a bit big.
Recheck your weight every 10 dives or so. You will need less weight as you gain more control and excess weight is poison for bouyancy control.

 

[sarysa]

I found that getting comfortable with my dry suit required me to change other things, so it wasn't really a matter of just doing a bunch of dives. Switching to power fins (negative buoyancy) and learning a proper trim more or less stopped any mishaps from happening with my dry suit.

 

[rhwestfall]

let you know when I get there..... (had it for 8 years)

 

[Wookie]

I don't understand this concept of "runaway ascents". I've only made 10 or a dozen dives in my drysuit. I put enough air in so that the inflater doesn't rub a hole in my chest and I go diving. If I'm neutrally buoyant at 100 feet, it doesn't matter if the air is in my feet, chest, arms, or on my back. I'm neutrally buoyant. In fact, if the air is in my feet and I'm feet up, head down, it makes it easier to fin and descend, not ascend out of control. If all of the air is in my feet and I don't want it there, I bend at the waist, put my legs down, and get ready to add air, because some is likely to burp out when it hits my dump valve.

Can someone please explain the mechanics of "runaway ascent"?

 

[altaskier]

Can someone please explain the mechanics of "runaway ascent"?

As you ascend, the pressure of the water outside the suit decreases so the air in the drysuit (and the BCD bladder) expands. That makes you more buoyant, which increases your ascent rate. Those are the mechanics.

Of course the solution is to make sure that your drysuit dump valve is at or near the highest point on your body, and that it is releasing air as you ascend. If your dump valve is closed too tightly (i.e., a higher differential pressure is required between the inside of the suit and the outside water pressure before air will leak out of the dump valve), or your dump valve is held too low relative to other parts of your body (like your left shoulder is low and your right arm is high), you can have problems with the ascent.

 

[GrumpyOldGuy]

Depends what you mean by comfortable.

The first few (2-3) dives I was unsure of myself. Like learning to dive again. I practiced ascents, purposely went feet up with a little too much air in the suit, etc... near a line I could grab on to if needed. I never did, the auto-dump valves worked as promised and it really is not that difficult to get back upright, just a another skill to learn.

The next 10-12 dives I was getting comfortable at times, but every once in a while (OK every 10-20 minutes) I would screw up (trim wise) and stir up the bottom like a student (a humbling but not life threatening experience). I tweaked my weights and undergarments constantly in this time.

I am now at about 25 dry dives and don't screw up often, but Mr. Murphy still hangs around waiting for his chance and odds are I will give him another shot at me. I have not mastered the dry suit yet and the near automatic buoyancy and trim control I have in a wet suit is not there. I am warm and dry though and eventually I hope it will return.

 

[spectrum]

I pretty much agree with the ball park 10 number. Mastery is a big term so let's say that you will be roughly on par with your prior wet skills.

For me the biggest trick was dialing in my configuration. Observe intensely and adjust as needed for each dive solicit buddy observations. How much weight and where you place it is really important. The basic skills of diving the drysuit are pretty basic but there is much less room for distraction and task loading until you get really familiar with what you need sense and how to react.

The risk of a runaway ascent is partially proportional to the depth of the dive and your (willingness) need to inject air to support garment loft for warmth. Air in the drysuit will expand on ascent just as it does in a BC. The catch is that you have limited vent locations, almost exclusively 1 so getting it to the high point is essential. Secondly a drysuit vent has nowhere near the rate of most BC dumps so it can be a lot harder to get a situation under control if it gets away from you. On a shallow dive some divers will limit the air added and deal with the squeeze. When I used a neoprene suit which had a lot of inherent warmth I'd often dive to nearly 30 feet with no air added.

The real skill is diving with enough air to be warm and unrestricted and being able to vent without major gyrations and contortions.

Mastery, what's that?

Pete

 

[Wookie]

OK, so if you control your buoyancy with your garment that is keeping you warm instead of your buoyancy control device, bad things can happen. Seems to me that the right amount of air is whatever loft your undergarments trap. Doesn't seem like rocket science, not does it seem that anyone with any amount of sense would find this a problem.