Underwear Ripoff...?

[mossym]

Well, there is always some suit squeze, but the entire point of dry suit diving is that you are keeping the undergarments from being compressed with your air supply! It's wet suits that get compressed at depth...

some undergarments need a lot of air to keep warm , and it's you that you're keeping from being compressed, not your undergarments...

 

[doctormike]

some undergarments need a lot of air to keep warm

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Perhaps true, something like a down comforter would probably not work as well if it was a bit compressed.. but like all physical things, there are operating limits. Insulating abilities would not go to zero with a small amount of compression.

and it's you that you're keeping from being compressed, not your undergarments...

Not true. The dry suit inflator controls the pressure inside the suit, which includes you and your undergarments. There is no pressure gradient between the surface of the underlayer and the surface of your skin. This is the whole point of dry suit diving.

If you are wearing a wet suit, it will continually be compressed and lose buoyancy and insulation the deeper you go. This is because the air cells in the wet suit are sealed, and have no way of adding or removing air. Since the walls of the cells are compressible, they get smaller with depth.

In a dry suit, you continually add air as you descend and vent as you ascend to maintain sufficient pressure to keep the underlayer filled with air (and insulating). Sure, if you get behind in your equalization, there will be a pressure gradient (with suit squeeze), but the idea is to keep enough air in the suit to keep the undergarment working.

 

[mossym]

,




Not true. The dry suit inflator controls the pressure inside the suit, which includes you and your undergarments. There is no pressure gradient between the surface of the underlayer and the surface of your skin. This is the whole point of dry suit diving.

agreed there is no pressure difference, but if you are ewaring a very lofty garment, and barely remove the aqueeze on your body, then the undergarment may not provide all the warmth it can..

if you have 2 insulators, that provide the same warmth, but one is twice as thick as the other...and as far as i know, and this could be where i am wrong, but these rely on trapping air in the material to keep the warmth, so that if you squeeze them they have no warmth...well you are going to have to add more air to allow the thicker one to expand fully...i like less air in my drysui...

i could be way off the mark though..

 

[doctormike]

agreed there is no pressure difference, but if you are ewaring a very lofty garment, and barely remove the aqueeze on your body, then the undergarment may not provide all the warmth it can..

if you have 2 insulators, that provide the same warmth, but one is twice as thick as the other...and as far as i know, and this could be where i am wrong, but these rely on trapping air in the material to keep the warmth, so that if you squeeze them they have no warmth...well you are going to have to add more air to allow the thicker one to expand fully...i like less air in my drysui...

i could be way off the mark though..

Well, the point is that the more a garment that relies on trapped air is squeezed, the less warmth it provides. This is especially true for open cell stuff (like dry suit underwear), but it is true to a degree for wet suits as well. Wet suits do more than just provide insulation from their air cells (blocking conductive heat loss), they also restrict flow of cold water past your body (blocking convective heat loss).

So if you don't put any air in your dry suit, it is true that you will progressively lose warmth as you descend (not to mention getting a BUNCH of hickeys!). But you do put air in your suit, and ideally you should have suffficient weight so that you can inflate your suit enought to keep the underwear lofty and warm. If you are underweighted, you may find that you can't stay down when you put enough air in the suit to keep your underwear fluffy.

Bottom line is that you are correct that if you keep your dry suit crushed against your body, your underwear won't work very well. So it is best not to do that...! But if you really like to avoid overinflation, then a heavier layer will resist the crush better than a thinner layer- all other things being equal.

 

[Don Burke]

Well, there is always some suit squeze, but the entire point of dry suit diving is that you are keeping the undergarments from being compressed with your air supply!

The effectiveness of most insulation is less if you are laying on it since it is designed for a vertical person in the snow. Compression will happen due to diver weight even if the suit is in the full Michelin Man mode. That is why some manufacturers use the boot sole type Thinsulate for drysuit undergarments.

Warmth costs, so you have to decide how much you need. The first $100 buys considerably more warmth than the third $100, which goes pretty much the same way as other things in the world.

Getting a car to go 100mph costs a certain amount. Getting it to go 200mph costs quite a bit more. 300mph might cost several times what 200mph did and 400mph is getting into cubic dollars. Such is life.

$500 dollar undergarments are cheap if you can not make the dive without them. They are a waste of money if Wallyworld sweats would have done the job.

I have used everything from shorts and a t-shirt to Thinsulate. Use what works for what you are doing.

 

[doctormike]

Getting a car to go 100mph costs a certain amount. Getting it to go 200mph costs quite a bit more. 300mph might cost several times what 200mph did and 400mph is getting into cubic dollars. Such is life.

$500 dollar undergarments are cheap if you can not make the dive without them. They are a waste of money if Wallyworld sweats would have done the job.

I have used everything from shorts and a t-shirt to Thinsulate. Use what works for what you are doing.

Good point... so... what would you guys recommend for Dutch Springs (a quarry, 48 degrees at depth last week) and for the New Jersey shore in the summer...?

Right now I'm leaning towards TPS thinsulate (?strecth) from DC (regular, not extreme)

 

[boatdiver842]

EXCELLENT replies, everyone.. and so fast, too! That's why I love ScubaBoard...

OK, so the early results seem to indicate that it's not just a question of using ski underwear, and that dive underlayers really do matter. NOW, the question is, what is the price breakpoint..? You can get a $5 bottle of wine, you can get a $50 bottle of wine and you can get a $5000 bottle of wine. The $5 bottle might taste OK to 20% of the market, the $50 bottle might satisfy another 75%, and there will always be a few people who won't be happy without the top of the line...

SO, where is the "sweet spot" in dive underwear...? I'm going to look on eBay, but assuming that I'm not doing any ice diving, what would be the basic acceptable comfortable recommendation of the group? I dive in Dutch Springs, and the temperature at depth was 48 degrees last week. I don't mind spending a bit more if it is really worth it... I saved a few hundred dollars by going with Diving Concepts instead of DUI...!

check out the Weezle under garment. I think you'll like it.

 

[Don Burke]

Good point... so... what would you guys recommend for Dutch Springs (a quarry, 48 degrees at depth last week) and for the New Jersey shore in the summer...?

Right now I'm leaning towards TPS thinsulate (?strecth) from DC (regular, not extreme)

When I got my Bare drysuit, I got the lightest Thinsulate undergarment they had. I do not recall the weight of the Thinsulate.

With a nylon t-shirt and shorts underneath the undergarment, a 7mm Henderson Goldcore hood and some hefty 100% wool socks, the issue in 35 degree water (which I do not get a chance at very often living in the Norfolk area) is keeping my hands from freezing, which I am still experimenting with.

Double neoprene gloves preloaded with warm water is the best I have tried so far. I have not tried dry gloves yet. I intend to try latex gloves under the double neoprene (also preloaded) before I go to a dry glove.

Head, foot, and hand insulation seem to be driving the problem at this point.

My first guess on what I would do if whole body insulation needs to be upgraded would be polypropylene under my current undergarment. If that does not do it, the next heavier Thinsulate goes on my shopping list.

 

[doctormike]

When I got my Bare drysuit, I got the lightest Thinsulate undergarment they had. I do not recall the weight of the Thinsulate.

With a nylon t-shirt and shorts underneath the undergarment, a 7mm Henderson Goldcore hood and some hefty 100% wool socks, the issue in 35 degree water (which I do not get a chance at very often living in the Norfolk area) is keeping my hands from freezing, which I am still experimenting with.

Double neoprene gloves preloaded with warm water is the best I have tried so far. I have not tried dry gloves yet. I intend to try latex gloves under the double neoprene (also preloaded) before I go to a dry glove.

Head, foot, and hand insulation seem to be driving the problem at this point.

My first guess on what I would do if whole body insulation needs to be upgraded would be polypropylene under my current undergarment. If that does not do it, the next heavier Thinsulate goes on my shopping list.

Yup... my hands are usually OK even in the 40s with wet gloves... have tried dry glove systems at the DUI demo days a few times, and I prefer having my hands free untill show time. Might be a different story in the 30s!

I ordered the dry suit today... very exciting!

 

[doctormike]

check out the Weezle under garment. I think you'll like it.

Yup- had heard good things (works when wet, good insulation) and bad things (fit problems) about the Weezle, but I think that I'll take a look...