What is covered in a PADI drysuit diver course?

[Storker]

if I were diving a recreational single tank setup and if I were properly weighted, if I put enough air in the suit to be comfortable, I wouldn't need anything in the suit to maintain buoyancy

As a single tank drysuit diver, this is very much how I do it.

At the start of the dive, roughly at SS depth, I have about the same lift in my wing as the weight of the gas I'm going to use during the dive. IOW, some 2-3 kg. During the dive, just compensating for squeeze on descent or venting extra buoyancy for the suit on acscent does most of the job. During the dive, I slowly vent my wing by the loss of weight as I use up my gas.

So, short-term buoyancy swings are handled by me adjusting squeeze. Long-term buoyancy swings are handled by slowly venting the wing by the weight of the gas I consume. Rather different from diving a wetsuit.

 

[Diving Dubai]

From my perspective, and while I've used a D?S for the last 5 years I consider myself merely competent rather than proficient

My D/S was good, but its only a couple of OW dives which basically teaches you the basics but you do need practice. I was introduced to both D/S for buoyancy and wing for buoyancy methods

I underestimated the competency needed (or overestimated my competency) for my local diving which involved currents.

I was in denial about the amount of weight needed - diving wet I needed very little, so kept reducing mine to what I thought was right. I ended up underweight a few times, looking like a fool.

Finding a good way to carry the weight for boat diving (climbing ladders) and distributing it

I imagined a D/S would dump gas as fast as a BCD. it doesn't. So I ended up using wing for buoyancy. Found that I needed to get myself sorted at the 10m mark - regarding managing buoyancy - generally I'd put suit into squeeze and balance my buoyancy on my wing - Yes I moved to overweight rather than risk corking

Getting auto dump sorted. I would leave it wide open and then forever be adding air to avoid squeeze

I don't like the restriction the D/S gives me for finning over wet. I would rather dive a 7mm than my D/S but I do appreciate my D/S at certain times

I have a hate hate relationship with my suit so use it only when I absolutely need to, which of course means I don't get the practice I should. Most of the time I can get away with a 7mm and hood, that's easier than persevering and getting more proficient

 

[boulderjohn]

This weekend I had a drysuit flood, and circumstances led to me diving in a 7mm wetsuit instead. I was wearing heavy doubles and doing tech training. Doing those dives in a wetsuit for the first time was a revelation--I realized how much I used the drysuit for buoyancy control when I didn't have it for the first time. It was not until my 4th dive with a wetsuit that I was comfortable on the deco stops.

 

[drk5036]

I don't know squat about dry suit diving yet. But dang those Neotek semi-dry's are the bomb for cold water!

I...can’t do it. Maybe I’m a baby, I’m not sure. The water here now is 16 degrees. About 61F. I made it through two 40 minute dives, but I was cold. I guess I’m going to be the guy wearing a semidry in the 75 F water, haha.

 

[drk5036]

As a single tank drysuit diver, this is very much how I do it.

At the start of the dive, roughly at SS depth, I have about the same lift in my wing as the weight of the gas I'm going to use during the dive. IOW, some 2-3 kg. During the dive, just compensating for squeeze on descent or venting extra buoyancy for the suit on acscent does most of the job. During the dive, I slowly vent my wing by the loss of weight as I use up my gas.

So, short-term buoyancy swings are handled by me adjusting squeeze. Long-term buoyancy swings are handled by slowly venting the wing by the weight of the gas I consume. Rather different from diving a wetsuit.

This is really good advice, thanks!

Do you keep the auto dump fully open and just maintain a shoulder-down position, or tighten the dump a few clicks at depth?

 

[rjgiddings]

Getting out of an ascent - when your drysuit legs are way floaty - is the one skill I remember teaching the most during my old PADI divemaster days. You kick like hell until you can get those legs back down then dump air quickly from the left shoulder vent.

I love my CF200x drysuit and wont go back to a wetsuit in Puget Sound. Cause that's crazy talk.

 

[Storker]

Do you keep the auto dump fully open and just maintain a shoulder-down position, or tighten the dump a few clicks at depth?

Le gustibus and all that, but I prefer to dive with an open dump valve. A couple clicks in to keep the valve from letting water in. Since a suit vents slower than a wing, I vent often and in small amounts as soon as I'm feeling a little light, by just rolling a little to my right and lifting my left elbow.

Be aware, though, that if you lose trim, e.g. go vertical to shoot a picture, the suit will start venting. If you're on a wall, that could become a bit awkward. And for safety, you have to train to close the valve no later than as you surface. I often do it on the SS, since that enables me to go vertical to look for boats on the surface. I guess that's why we were taught to dive with a closed valve during OW class and to vent manually by pressing the valve in.

And on the weighting thing: I'd rather carry a couple kg "too much" than being underweighted. You need some gas in your suit to loft your undergarments. If you're squeezed, you'll freeze. Weight is warmth.

 

[Edward3c]

This is really good advice, thanks!

Do you keep the auto dump fully open and just maintain a shoulder-down position, or tighten the dump a few clicks at depth?

The spring pressure is different on each suit. I’m on my fourth, from the same manufacturer, and the number of clicks to hold the bubble size has been different on each one.

* When messing round on the surface pre-dive I have the valve fully open and stay afloat with my jacket.
* To descend all I have to do is dump the jacket.
* At around 6m we do a bubble check - that’s where I screw the value down so it holds the bubble I need to maintain neutral buoyancy.
* During the dive I either input or manually dump air as required. (Dives over 30m I’ll use the jacket as well.)
* On the ascent I’ll dump as required and once above 10m will open the value a few more clicks.
* In the last 2m I will close the valve and input air into both the suit and jacket once on the surface.

 

[drk5036]

The spring pressure is different on each suit. I’m on my fourth, from the same manufacturer, and the number of clicks to hold the bubble size has been different on each one.

* When messing round on the surface pre-dive I have the valve fully open and stay afloat with my jacket.
* To descend all I have to do is dump the jacket.
* At around 6m we do a bubble check - that’s where I screw the value down so it holds the bubble I need to maintain neutral buoyancy.
* During the dive I either input or manually dump air as required. (Dives over 30m I’ll use the jacket as well.)
* On the ascent I’ll dump as required and once above 10m will open the value a few more clicks.
* In the last 2m I will close the valve and input air into both the suit and jacket once on the surface.

This is a nice description, thanks! So when you do your bubble check at 6m, what your are doing is setting the valve so that at that specific pressure, you will maintain that buoyancy. If you lift your arm, it will not vent, but if you were to rise one meter, with your arm raised, it should then vent, correct?

effectively, you are maintaining your “neutral buoyancy” pressure by setting the valve, which just means you don’t have to worry as much about your arm position? Even if you lift your arm, it should only dump to your “neutral buoyancy” inflation level?

the theory is clear to me, it’s harder to explain I guess. Really helpful!

 

[Storker]

effectively, you are maintaining your “neutral buoyancy” pressure by setting the valve, which just means you don’t have to worry as much about your arm position? Even if you lift your arm, it should only dump to your “neutral buoyancy” inflation level?

I know you're replying to @Edward3c here, but I've never been able to set the shoulder valve so it just keeps my bubble the right size by itself. In horizontal trim, even a nearly open valve shouldn't vent, but as soon as you roll a little to the right and lift your left elbow it will start venting. I'm controlling both filling and venting my suit. Even a fully open valve shouldn't vent if you're in horizontal trim, but it may let in a little water so your upper arm gets wet. Thus the couple clicks in.

As long as my suit bubble is about the right size, I only fill and vent my suit, not touching the wing inflator. If I'm getting a bit light and start feeling squeezed, it's time to dump a puff or two from the wing and get the suit bubble back to a comfortable size.

On descent, if I'm neutral and with a right size suit bubble at the bubble check, I don't add much - if any - gas to my wing on descent. Taking off the squeeze will bring the suit bubble back to its original size, and my buoyancy will go back to neutral quite automagically. If I drop quickly, I might choose to stop the descent by adding some gas to my wing, and when I've stopped my descent I fine-tune the suit bubble vs wing buoyancy.