Will drysuit diving suck less soon?

[MXGratefulDiver]

I do it differently than the apparent majority in here. I use my suit for buoyancy control. Before anybody jumps in to tell me how I'm "DIW", I'll point out that I've got about 430 dives on this suit in the past year and a half, and never had any buoyancy issues in any orientation ... it took me about 10-12 dives to learn how to be completely comfortable. I leave my shoulder dump set fully open all the time, wear the minimum amount of weight, and never have experienced any issues with air shifting around in my suit.

I own a custom-cut Diving Concepts trilam ... and I have to say they did a great job of creating a suit that fits me well. Early on I added a pair of gaitors to prevent air from going into my boots when I invert ... and they're quite effective. During a dive I will often go completely upside down to peer under a rock or ledge, and have never experienced the urge to head to the surface fins-up.

I learned to use my drysuit for bouyancy control simply because that's the way the manufacturer recommends ... and it works fine for me. Some of my DIR-trained buddies tried to convince me to use my BCD instead, using exactly the same arguments I've read in here. I tried it for a few dives. But to be honest, I feel more comfortable using my suit. And to be equally honest, I've only dove (dived?) with a very few people who have better buoyancy skills than I do ... and among those are divers who use either method.

As for the comments about potential failure points ... well, in my time underwater I've seen more BCD failures (six) than I have drysuit failures (one) during the course of a dive. I'll choose to play the stats on this one, and rely on what in my experience seems to be the more reliable piece of gear. FWIW - in the event of a stuck inflator you're going to be able to disconnect and vent from a drysuit much faster than you will from a BCD.

Bottom line ... the "correct" method is the one that you, the individual diver, are most comfortable with. The "best" method is really going to depend on the type and fit of your drysuit, and how you are trained to use it.

.. Bob (Grateful Diver)

 

[DA Aquamaster]

This has been an interesting thread. At first I disagreed with using a BC or wing for bouyancy with a dry suit. Then I realized that based on my experience and the way I dive this long held view was probably not entirely consistent with how I actually do it.

But then it also occurred to me that overweighting is potentially the root cause of many of the concerns raised with using the drysuit for bouyancy control.

You only need enough air in the suit to avoid a squeeze and provide the room for the insulation to do it's thing to keep you warm and the diver should weight himself accordingly and be very vigilant about not overweighting.

Many dry suit divers, in my opinion, use too much weight and consequently too much air in the suit which leads to the above mentioned concerns for air shifting, etc.

But under normal curcumstances if you keep the minimum amount of air in the suit to avoid a squeeze and weight yourself accordingly to achieve neutral bouyancy at the end of the dive with that amount of air in the suit, you will not really need to use the BC for bouyancy control as any suit compression with depth will result in a squeeze that needs to be corrected with air which will at the same time neutralize your bouyancy. The additional volume for 4-5 lbs of additional bouyancy needed at the begining of the dive is slight and should not be a factor, provided you are not overweighted to begin with.

So if the diver is properly weighted and uses good technique, I really don't see a role for a BC in primary control of bouyancy unless you are using stage bottles or something else that would require additional bouyancy from the BC or wing. In that case the BC or wing suddenly becomes a key player in the bouyancy issue.

But short of that, in plain jane OW diving, the need to use the BC for bouyancy control to avoid excessive air in the suit would seem to indicate an underlying problem of wearing too much lead in the first place. I don't think using the BC to add extra lift is the most parsimonious solution to the problems that result.

 

[Braunbehrens]

DA Aquamaster once bubbled...
This has been an interesting thread. At first I disagreed with using a BC or wing for bouyancy with a dry suit. Then I realized that based on my experience and the way I dive this long held view was probably not entirely consistent with how I actually do it.

But then it also occurred to me that overweighting is potentially the root cause of many of the concerns raised with using the drysuit for bouyancy control.

You only need enough air in the suit to avoid a squeeze and provide the room for the insulation to do it's thing to keep you warm and the diver should weight himself accordingly and be very vigilant about not overweighting.

Many dry suit divers, in my opinion, use too much weight and consequently too much air in the suit which leads to the above mentioned concerns for air shifting, etc.

But under normal curcumstances if you keep the minimum amount of air in the suit to avoid a squeeze and weight yourself accordingly to achieve neutral bouyancy at the end of the dive with that amount of air in the suit, you will not really need to use the BC for bouyancy control as any suit compression with depth will result in a squeeze that needs to be corrected with air which will at the same time neutralize your bouyancy. The additional volume for 4-5 lbs of additional bouyancy needed at the begining of the dive is slight and should not be a factor, provided you are not overweighted to begin with.

So if the diver is properly weighted and uses good technique, I really don't see a role for a BC in primary control of bouyancy unless you are using stage bottles or something else that would require additional bouyancy from the BC or wing. In that case the BC or wing suddenly becomes a key player in the bouyancy issue.

But short of that, in plain jane OW diving, the need to use the BC for bouyancy control to avoid excessive air in the suit would seem to indicate an underlying problem of wearing too much lead in the first place. I don't think using the BC to add extra lift is the most parsimonious solution to the problems that result.

Your comments are interesting. I agree that overweighting is a major problem for many divers.

However a bubble of 6 pounds of lift is not insignificant to have shifting around in your suit. 6 lbs is about 3 kilo's, which is equivalent in weight to 3 liters of fresh water. So the size of the gas bubble is about the size of 3 large bottles of water, or about a third less than a gallon jug.

This gas will migrate to the highest point, it's NOT distributed throughout the suit.

For technical dives tihs is even more pronounced, although not as much as one would assume, due to the lower weight of helium.

 

[ColdH2Odvr]

double125's once bubbled...
Is it possible to set the valve to lite and it doing the reverse: creating a suction and allowing water in.

IMHO, no.

Though it is theoretically possible to drive the pressure in your suite below ambient, for all practical discussion, it’s impossible, ain’t gonna happen, you wouldn’t survive the squeeze. Even if it did happen, all drysuit valves I’ve seen are spring assisted (shut) check valves. If water pressure were above suite pressure, it would only serve to force the valve shut. That said, there’s one constant with check valves, they leak. It’s not at all impossible to get leakage through a suit valve from fuzz from your thermals, etc. Fortunately, I’ve not seen it happen so I don’t know if this is even a significant concern.

Dave

 

[double125's]

Thanks dave, I had it out again today and got to test it to 70' and no leakage. Water was in the mid 50's at depth.

 

[Braunbehrens]

ColdH2Odvr once bubbled...


IMHO, no.

Though it is theoretically possible to drive the pressure in your suite below ambient, for all practical discussion, it’s impossible, ain’t gonna happen, you wouldn’t survive the squeeze. Even if it did happen, all drysuit valves I’ve seen are spring assisted (shut) check valves. If water pressure were above suite pressure, it would only serve to force the valve shut. That said, there’s one constant with check valves, they leak. It’s not at all impossible to get leakage through a suit valve from fuzz from your thermals, etc. Fortunately, I’ve not seen it happen so I don’t know if this is even a significant concern.

Dave

I don't see how the pressure could go below ambient. The suit is flexible, so it will just flatten out against your skin. To get it below ambient you'd need a hard shell, wouldn't you?

My shoulder dump likes to leak. It's a pain in the neck. In my experience some valves like to leak, some don't.

Apeks had to switch the design on the bottom of the flat variable dump because it allowed stuff to get into the valve.

 

[ColdH2Odvr]

Braunbehrens,

I gave a nod to the theoretical possibility for two reasons 1) To ward off a long thread with any hyper literal readers, and 2) To cover myself if I had my head up my butt when I wrote the post (a frequent occurrence). Theoretically, if you dove deep enough to get ‘all’ of the air out of your suit, the rebound of your thermals might be sufficient to lower pressure in the suite below ambient (like putting your fist in a latex glove then opening your fist). Again, not practical, ain’t gonna happen, insignificant. Sorry, I’m not trying to confuse the issue, just covering my butt (or my head, depending).

I guess I’ve just been lucky with my dump valves, knock on wood. Have you pulled yours apart to see if it can be cleaned?

PS: Good man dbl125, I’ve been grounded with a persistent cold and my drysuit has gotten way too dry.

 

[Braunbehrens]

ColdH2Odvr once bubbled...
Braunbehrens,

I guess I’ve just been lucky with my dump valves, knock on wood. Have you pulled yours apart to see if it can be cleaned?

Yeah, I've had it apart a few times, and I've had the suit pressure tested a few times. It always seems that everything is AOK, but I often feel cold during my dive and after getting out realize that it's due to a wet left arm.

My guess is that the design of the valve isn't all that great. I should have gone with the old style (bulky) apeks, instead I went with sytek.

 

[MXGratefulDiver]

Apeks seems to be having some problems with their dump valves too ...

I've replaced mine because of chronic leaking ... and the replacement valve also leaks. I know several other friends ... with suits from different manufacturers ... who also have the same problem.

My "solution" was to wear fleece next to my skin (under my DC undergarment). That way, even wet and under pressure I don't get cold. In fact, I don't typically even realize I'm wet until I take off the drysuit.

... Bob (Grateful Diver)

 

[jkromelow]

double125's once bubbled...
My only concern is I am a little damp when I surface. I cant figure if it is just sweat...

What kind of thermals? Anything with cotton with end up wet from persperation. The first time I used a dry suit all I had were thermals that had cotton. I thought there was a leak. Tried the new synthetics -coolmax- and ended up dry as a bone. Materials that wick moisture away from the skin are key. It isn't just marketing BS.