Bone To Pick with PADI Dry Suit Cert.

[Trace Malinowski]

Even if it were a PADI policy, you really couldn't blame them if it came to legalities. They'd probably just be following the manufacturer's instructions for drysuit use. What blows my mind is when I read the instruction books provided by the manufacturers themselves. Most do not have a clue about how to dive the drysuits that they make.

My question to students regarding drysuit use:

"Is it easier to vent gas from your wing or from your drysuit during ascent? Which will vent more efficiently?"

Swimming = immediate buoyancy correction. If you find yourself ascending too fast, swim down or up. (This will work if the diver has the ability to maintain trim. This is why trim is an important tool. It allows the diver to instantly assume a body position of having the feet angled SLIGHTLY up or down to immediately correct a buoyancy issue.)

BCD/Wing = delayed buoyancy correction. It will take a little time to vent gas from either the OPV/dump valve (preferred primary dump) or the corrugated oral/auto-inflator hose (secondary dump). If a diver is ascending too rapidly, he or she may not be able to dump gas in time relying upon the speed of exhaust alone. The ability to propel oneself and vent becomes important. If a diver needs to kick down against a runaway ascent, venting from the bottom OPV/dump will allow gas to exit as the diver retards his or her ascent with efficient kicks. By making the rear dump, the primary dump, the diver will be able to maintain a horizontal or slightly feet up angle of attack which is beneficial for anti-silt, anti-damage and better control during ascents. A horizontal diver dumping slightly feet up presents a larger surface area to help control the rate of ascent. A vertical diver isn't as easily slowed due less surface area being presented in the direction of motion (Up).

Drysuit = very delayed buoyancy correction. A drysuit has a large surface area with many pockets of trapped gas. If a drysuit is used as a primary buoyancy source, the speed at which gas is vented may not keep up with the speed of ascent.

For these reasons, the primary source of buoyancy should be the BCD/wing with just enough gas added to the drysuit to offset squeeze. The diver needs the control to make minute or emergency corrections with his or her feet while dumping gas, or adding gas, until a basic prone control position can be re-established.

I just love the diving industry. A drysuit specialty class is normally one day. The student who comes into class often does not have very good trim, buoyancy or propulsion in a wetsuit. With little time given to developing the fundamental skills of control. The student is often equipped in a poorly fitting drysuit (because the cuts on most drysuits are substandard) which can trap gas and lead to rapid ascent. The student is shown bad habits for use of the suit which will make trim, buoyancy and propulsion even more difficult to manage, and skills problems are solved by equipment solutions such as adding ankle weights, rather than being solved by good coaching and adequate time to develop proper skills. The student now is wearing extra weight, has less comfort in the water than before (except perhaps thermally), and is often swimming in a vertical position and working harder. Diving in cold water areas becomes too hard and too exhaustive and local divers drop out to proudly become warm water wusses and give far less financial support to the shop that certified them in drysuit diving. And, all this can be yours for FREE with the purchase of any drysuit!

 

[Scott]

I might understand where the instructor is coming from Steve and why some consider using both task loading.

One of the first dry suits I had, had the shoulder vent that you either leaned your head against to depress the vent or used the opposite hand to push the button. No fancy adjustable vent.
Doing this while trying to vent the BC at times was not fun if caught in the wrong position.
Another suit I still have has a wrist vent on the left side. Both types were tricky to vent in the beginning or if you were out of position/trim.
When I first started using those two suits I found it was easier to use the suit for buoyancy than the BC or a combination of the two.

Had a student came to me with those same suits I may have considered telling them to use the DS in the beginning based on my experiences. This may be what your instructor was doing, drawing from the past.

We need to look at what the student is using, their skill level, goals and attitude and incorporate that into the course. While mine is close to the course D_B described it changes some with each class.
As an example, I know from other posts Steve has a Fusion. From the one time I used a Fusion I would not even considered using it for buoyancy.
To me it would take away from fit more so than a typical tri-lam.
For those who own one. Would you consider a Fusion a tri-lam?

SteveR1952 putting the BC/DS buoyancy issues aside did you learn anything else from the class? If so then it wasn't a total waste.
You have now found a better way to dive dry, go and play my son.

I hope to be in your neck of the woods in Dec with a DS class. Dress warm and come play with us.

 

[boulderjohn]

I believe I read from from past threads on this topic that NAUI also teaches to use the dry suit for buoyancy.

Here is a quote from Dry Suit Diving: A Guide to Diving Dry (4TH Edition) by Steven Barsky, Dick Long, and Bob Stinton:

Once you reach the bottom, adjust your buoyancy using only your your dry suit so that you are neutral. Do not add air to your buoyancy compensator to adjust your buoyancy. It is very difficult to control your buoyancy when you have air in two separate compartments at the same time, i.e., the B.C. and your suit. Controlling both air compartments is an advanced skill and is not recommended for the novice dry suit diver. (p. 94)

By the way, Dick Long is the founder of DUI, and Bob Stinton is the Vice-President of engineering for DUI.

OK, so we can see that PADI is not alone in this recommendation.

Now that PADI has been totally ripped for this, as usual, will we now see some similar posts ripping SSI, NAUI, DUI, and the most well known textbook on dry suit diving as well?

 

[Sas]

I do primarilly use my suit for bouyancy without any fuzz..
Then again, what I need to offset the squeeze is the same or close to the same as I need for bouyancy..

Yea me too.

Despite what a lot of people say on the internet, there is no right way when it comes to what to use for buoyancy. I use the suit as per the comment quoted and I don't find trim a problem at all. Sometimes on very long shallow dives I will overweight myself by a little bit just to keep more air in my suit as well.

Make sure you are weighted correctly, try out both methods and see what you prefer.

 

[fnfalman]

There's more than one way to dive a drysuit. Plenty of people have done it in both ways and come out just fine.

Pick a technique that you like and hone your skills on it.

My preference is to use the BC so that my muscle memory doesn't get all screwed up when diving with wetsuit or no wetsuit. But that's "MY" preference. I don't really care what PADI or DUI or SSI say. They ain't divin' my suit. I am.

 

[Sas]

My preference is to use the BC so that my muscle memory doesn't get all screwed up when diving with wetsuit or no wetsuit.

Heh, that's true After an unseasonally warm spring, I am back in my wetsuit nearly two months early. The first few dives whenever I needed to adjust my buoyancy I would press on my chest where the inflator button usually sits

 

[Codiak]

One other consideration, as a general rule no one checks dry suit C-Cards.
If you bring your own it's assumed you know what your doing.

I'd be less worried about being "certified" and figureout what works for you.

 

[Gombessa]

One other consideration, as a general rule no one checks dry suit C-Cards.
If you bring your own it's assumed you know what your doing.

Man, I would be flummoxed if I brought my drysuit onto a boat and the crew asked to see a drysuit specialty card

 

[boulderjohn]

Man, I would be flummoxed if I brought my drysuit onto a boat and the crew asked to see a drysuit specialty card

I think the possibility of a check would occur if you wanted to rent a dry suit. I know our shop would want to have some indication that you knew what you were doing if you came in for a rental. (I don't work there, so I am not sure what they would do.)

 

[Tigerman]

...
Now that PADI has been totally ripped for this, as usual, will we now see some similar posts ripping SSI, NAUI, DUI, and the most well known textbook on dry suit diving as well?

Of course not, PADI is the devil!

Man, I would be flummoxed if I brought my drysuit onto a boat and the crew asked to see a drysuit specialty card

I would hand them my passport and ask them what kinda water theid expect me to be diving