Drysuit leak potential at various depths

[dive_turkey]

So, I have a question for those with a little more experience. I just recently finished my drysuit course and bought my first drysuit, but I have only been down to about 12m with it. The question I have is this:

As I go deeper in the suit, are the seals more or less likely to leak? I suspect they'd be less likely to leak, due to surrounding water pressure pushing the seals tighter against my skin.

Am I close? Am I way off base? Does it even matter?

Thanks!

 

[nimoh]

I think it should be the same. Yes you have greater pressure outside the suit, but you also have greater pressure inside the suit (assuming you are equalizing the suit).

Then again, why does it matter? You can't get more dry than dry.

 

[Doppler]

All things being equal, the performance of your suit's seals depends on their condition, the material they were made from, the geometry of your body, and how you behave as you go deeper.

However, as pointed out above... dry is dry

 

[raftingtigger]

As said above, for a given inflation level the differential pressure should be the same regardless of depth. This is different than a flashlight or camera case. The later are rigid cases and the internal pressure is not substantially changed during the dive. Therefore as depth increases the differential pressure increases as does the potential for leaks.

In a drysuit, to maintain the same displacement (buoyancy) the diver adds gas to the suit as depth increases. For all intents and purposes this keeps the differential pressure the same and therefore the leak potential the same. Movements do make a difference. IMHO surface movements tend to be bigger than submerged movements. As a result leakage is more likely at the surface.

---------- Post added October 4th, 2013 at 11:12 AM ----------

As an addendum. Again IMHO most of the leaking comes from the wrist seals. Easy way to prevent that is use of dry gloves. The other leak point is the neck seal. I find that using a hood allows a greater leak-free neck range-of-motion than without a hood.

 

[TSandM]

Remember that you add air to the dry suit as you descent, to prevent excessive squeeze. As a result, there will never be much of a pressure gradient at all across the suit or the seals. If the seals work well in shallow water, they will do so at depth. What makes seals leak is anything that breaks the contact between the seal and the skin. This can happen, for example, if you put enough air in the suit that it tries to bubble up and out the neck seal (which also tells you that the neck seal is a bit big, and you are head up). It can also happen if you move your wrists a great deal, and the tendons create channels that allow water ingress.

 

[dive_turkey]

Makes sense. I suppose I was thinking that since the seals lay flat against the skin they would seal tighter at depth. Even when there is a huge bubble in my suit (say just after putting it on and then doing the squat to purge the air), my seals still stay in contact with well over an inch of skin. I can't imagine my seals actually being pushed out by internal pressure.

The reason I ask: Initially my neck seal had only had about 3 rings cut off of it while I was in the class. The LDS didn't want to cut much further than that because there was uncertainty over who would end up buying the suit and how thick their neck might be. So, I was the only guy in the class with a neck skinny enough to tolerate the tight seal. It was tight, but did not cause any breathing or venus return issues, so it was tolerable, though uncomfortably tight. After buying the suit, I decided to dive it a couple more times before committing to trimming another ring off the neck seal. Donning the suit, during the dives, and doffing the suit, I was keenly aware of the neck seal's tightness. To a point where I was moving it up and down my neck trying to find the place it was least intrusive. Then I decided to cut it down. We cut one ring off and when I put the suit back on the neck seal seems perfect. It fits tightly around my skin, but doesn't feel at all restrictive. Of course, right now I have a head cold and had to cancel my dives for tomorrow, so it's killing me trying to think about how well that seal will work. Then I started to wonder about the depth and started to get really nervous, because I wasn't really sure how the seal would react through a deeper dive profile.

I suppose it's all in my head. I'm sure the seal will be fine. I just won't get to test it for another week, fingers crossed.