Checkout Dives in Oversized Drysuit

[ktchan]

Honestly, look several inches both in length and width better than the one I worn for my OW checkout dives.

Put a BC on, see how easy/difficult it is for you to take it off and back on (compared to normal). The folds from the excess material may make it difficult for you to do the remove and replace gear skill.

 

[ktchan]

That's good to hear. When I took the course, the PADI material was unequivocal when it came to rec trilam suits, "For all shell dry suits - that is, anything other than a neoprene dry suit - you will stop using your BCD until you return to the surface. Underwater, you control your buoyancy using only your dry suit, except in an emergency."

My instructor acknowledged this was what was in the text, but taught me to use the BCD anyway.

Still say that on PADI e-learning.

 

[inquis]

Still say that on PADI e-learning.

Not exclusively, however. When I took a drysuit class a few years back, the instructor indicated I should refer to the Advanced Open Water e-learning. An excerpt from the Drysuit Specialty chapter:

Controlling Your Buoyancy
How you make buoyancy adjustments underwater while diving dry has evolved over the years. At present, there are two basic methods that depend upon personal preference, weighting and manufacturer recommendations (always follow manufacturer recommendations). Your instructor will show you either or both methods, as appropriate for the suit you’re using, local practices and the situation.
Method One: Controlling buoyancy with only the suit. Don’t use your BCD (except to deal with an emergency like a flooded suit, if necessary) until you return to the surface. [...]
Method Two: Controlling buoyancy with your BCD. As you descend, add just enough gas to prevent suit squeeze, but don’t attempt to offset the entire buoyancy change with your suit. [...] This method works well with neoprene dry suits because they lose buoyancy due to compression of the suit material. You may end up with an uncomfortable amount of gas in the suit if you don’t also use your BCD for buoyancy control.

 

[lexvil]

What about offsetting the gas you breathe down from the tank? If you didn't add anything to your wing to stop the descent, then you've got 4-6 lbs of extra lift in your suit (assuming single tank) at the start of the dive. Obviously that isn't a problem for you. But I don't think it's a good idea for the OP and that suit, unless he really wants extra practice on his inversion recoveries

Just a little squeeze at the end of the dive and a little extra at the beginning but agree not a good plan in an oversized suit.

 

[FJUK1]

Thanks everyone for the input, I will dive the suit as is. As for buoyancy I have had a few discussions with my instructors and think the best method for using an oversized suit is to eliminate squeeze only and then use my wing as the primary device. Gives me less of a bubble to manage throughout the dive that could become trapped in the suit folding over itself etc.

 

[MikeHoncho]

Thanks everyone for the input, I will dive the suit as is. As for buoyancy I have had a few discussions with my instructors and think the best method for using an oversized suit is to eliminate squeeze only and then use my wing as the primary device. Gives me less of a bubble to manage throughout the dive that could become trapped in the suit folding over itself etc.

I agree except it will get caught in your legs. You won't be able to tell any different other than you'll go foot height but again, you will will be all over the place being new. If/when you find yourself getting foot high, remember that the air in your BC is also at the bottom (if standing) of the BC and venting through the hose will not work. You either need to dump from the bottom (if it has it) or get vertical. My experience with my OWC and dry suit cert combined is I went feet high, started ascending and tried to dump air from my BC which didn't do anything until I rolled, got vertical and dumped from the hose. It took me a couple dives to figure out why I always had a difficult time staying at depth above 20ft and it was because my trim was off and I had remaining air trapped in my BC and legs. Once I got it figured out, corrected trim all was right in the world. I inflate my suit for squeeze/comfort and use my BC for buoyancy. Its a heck of a lot easier to dump air from a bc that it is from a single valve on your arm in your suit.....but I'm still new.

 

[lexvil]

I agree except it will get caught in your legs. You won't be able to tell any different other than you'll go foot height but again, you will will be all over the place being new. If/when you find yourself getting foot high, remember that the air in your BC is also at the bottom (if standing) of the BC and venting through the hose will not work. You either need to dump from the bottom (if it has it) or get vertical. My experience with my OWC and dry suit cert combined is I went feet high, started ascending and tried to dump air from my BC which didn't do anything until I rolled, got vertical and dumped from the hose. It took me a couple dives to figure out why I always had a difficult time staying at depth above 20ft and it was because my trim was off and I had remaining air trapped in my BC and legs. Once I got it figured out, corrected trim all was right in the world. I inflate my suit for squeeze/comfort and use my BC for buoyancy. Its a heck of a lot easier to dump air from a bc that it is from a single valve on your arm in your suit.....but I'm still new.

Once you get used to it the arm dump is very natural and doesn’t require anything but a slight shift in position, a slight roll. You will/should learn to anticipate the changes as you change depth, venting is easier than adding air.

 

[tmassey]

It’s a heck of a lot easier to dump air from a bc that it is from a single valve on your arm in your suit.....but I'm still new.

Yup….

Hardest part of diving a drysuit. It’s the combination of the difficulty of feeling the change in buoyancy, and the fact that the actual dump will take a lot more technique and a bit more time to accomplish.

So why make that worse by putting more air in that suit than necessary?

The *real* secret for a drysuit is the same as it for all of diving: get your weighting correct! The *vast* majority of divers are overweighted, and they become even *more* overweighted when they start diving a drysuit. You need to be ruthless about dropping that weight.

And how much weight you need will *decrease* as you get more proficient. You’ll get better at managing the gas in the suit, you won’t get as much gas trapped in odd spots, and you’ll get better at getting it all out. That will all help you to need less lead to stay down. And the less lead you have, the less gas you need for buoyancy, and no matter *where* that gas is kept, it will be easier to manage.

When you have too much lead, you will need to keep a larger volume of buoyancy inflated. That volume will react to depth changes. The more volume you need, the more sensitive you’ll be to depth changes. When you’re weighted correctly, you can make even large depth changes (a number of feet easy) and still be at least close to neutral. With even 5 pounds of too much lead, that becomes more like inches, not feet. Even a change of 3 feet will start to throw you out of whack, requiring a manual gas adjustment.

And then go back to the fact that drysuits are just physically, mechanically more difficult than a BC to manage. And you now have two things to manage…. It’s gonna be a nightmare, and you’re gonna hate it.

So get your ballast down!

And like I said, this is a long-term battle. Stay vigilant. I went from 24 pounds at the beginning (right after my class, with an instructor who helped to ‘get my weight right’) to 10 pounds. I was proud: I didn’t know anyone who used so little lead in a drysuit! I switched at some point to doubles. My fundies instructor challenged me to drop more weight, and I didn’t think I could. Sure enough, I now use *zero* lead with all but the floatiest tanks (where I only use 4 pounds).

And diving a drysuit is now my preferred way of diving.

Of course, it took 50 or so drysuit dives to get there…. Be patient, and keep putting effort into it.

 

[MikeHoncho]

Once you get used to it the arm dump is very natural and doesn’t require anything but a slight shift in position, a slight roll. You will/should learn to anticipate the changes as you change depth, venting is easier than adding air.

Not when its stuck in your legs as a new diver with poor trim.....

 

[lexvil]

Not when its stuck in your legs as a new diver with poor trim.....

First 6 words, look ‘em up.