wet base layers, drysuit, and warmth

What fabrics are best under a drysuit with water in the mid to low 40s?

I use a polartec powerdry top and icebreaker wool bottoms. Both are absolutely drenched after I finish my workouts. So far I have stayed warm as long as I keep moving but am concerned that if I took a swim that the wet clothes would be rapidly chilled through the suit and perhaps even lead to hypothermia more quickly than if I wore a wetsuit. Any thoughts?

I understand the controversy that has emerged on some message threads here about whether one should wear a drysuit or not for cold water paddling. I have decided to wear one and just want to know if any base layers will keep me warm when wet, if the suit is submerged.


– Last Updated: Dec-02-09 6:39 PM EST –

My underlayers don't get drenched like what you describe, just the parts blocked from breathing such as where the PFD sits and over the gaskets.

However, I do have experience wearing rain-soaked garments while cycling. In my experience, wool works best for this. It will get heavy and soggy but still hold warmth. Fleece is OK but not as good, maybe because it's not as dense.

The real question is why are you so soaked under the drysuit? Is it a breathable fabric or coated nylon? Or are you wearing too many underlayers for the air temp and level of exertion?

Something to try: after your sweaty workout, go for a short swim. (Make sure you have a change of clothes ready.) How do YOU feel after the swim? Add some air inside the drysuit and see how that feels warmer. No, you don't want to paddle like Michelin Man, but this is something you can do after you're done, in case you do get chilled.

Maybe better synthetics…
…than wool these days, I don’t know. But my experience with short swims in wool outerwear over synthetic underwear in sub-freezing temps tells me that wool might do the job pretty well. Any time you can continue sitting in a duck blind after a brief drenching in the river in 15 degree air temps and still be comfortable means your gear is working well. That depends, of course, on how long you will be in the water.

Haven’t tested this with the dry suit yet though, so I’m interested in experienced replies as well.

Try polypropelene. Not the same as
"poly" which is polyester. Polypropelene knit has absolutely no affinitey whatsoever for water, and unlike Nylon and polyester, polypropelene fibers do not absorb any water.

However… I think what you are re-discovering is the fact that, when exercising hard, a person puts out more sweat than a drysuit can transfer to the outside atmosphere. I used to row and scull, and there is no way that a drysuit could have handled the amount of sweat that I put out when exercising hard, in cold weather.

Agree with g2d about poly pro

– Last Updated: Dec-02-09 8:24 PM EST –

With a Gortex drysuit, and with water temps as your describe in OP, here in Northern NY in the foothills of the Adirondacks in this "mild" December, I'm currently using mid weight polypro as an inner layer, and expedition weight poly pro as an outer layer.

My drysuit has integral Gortex booties, and I'm wearing light poly pro inner socks and wool outer socks, with Chota lace-up muckluks.

Have only used my fleece "bunny suit" rarely - in below zero fahrenheit air temps and with water temps turning to "slush".

Multiple 5 mile "fitness" paddles, without alot of sweat generated, using the above described clothing combo under a Gortex Dry suit, padling a canoe on flat water, and with spray deck for warmth.

Tomorrow, it may all be over and I'll be blowing feet of snow out of my sunken driveway, x-country skiing and waiting for spring ice out.

Hope this info helps.

Given up on synthetics…
…I’ve gone back to wool. I do sweat a lot and have used the Kokatat GMER for a while. When I was using synthetics I got cold and stayed cold. Now that I have switched back to wool I still get wet but stay way more comfy. I don’t chill like I did and don’t notice a difference in the time that I am wet, even though I know that I should).

I am an Icebreaker fan but their stuff is cut for guys who are young and skinny like I once was. I don’t want o embarrass myself so I’m exploring other makers and other cuts but intend to stay with Merino wool.

I read once that wool releases heat
when it is dampened. Don’t know if that is true. Of course, if you dry it on yourself, you or the environment will have to put back the heat that was released with wetting.

It’s about equally difficult for me to find suitable weaves and designs of wool or polypropelene undergarments. The market is flooded with polyester “wicking” stuff, which is better than cotton or Nylon, but still gets kinda sodden. How is stuff s’posed to wick effictively under a drysuit?

Agree about polypro
Polypro, worn as a base layer under wool or fleece, will wick moisture away from your body into the outer layers and keep your skin dry.

Wool (and fleece to a somewhat lesser extent) retain their insulating properties when wet. Then, as long as you have a waterproof barrier keeping cold water out, the moisture inside actually helps insulate.

This is the idea behind wetsuits; the trapped water forms an insulating layer inside the wetsuit. There is some exchange with the outside water, which is why wetsuits only work when the outside water’s warm enough for your body to heat it.

I like Merino Wool Too
I’ve gotten wool-underwear from http://www.wool-underwear.com They ship to the US, I don’t remember how long it takes but it wasn’t too bad a couple of years ago.

They have a combination deal for $149 delivered to the US:

1 x long sleeve (zip top or crew neck), 1 x short sleeve, and 1 x long johns (no fly)

If you buy more, the shipping isn’t as painful.

If you can deal with not having a fly, the goods are good quality, machine washable and thicker than most Merino wool stuff that I’ve seen.

"light fuse, get away"
My favorite example of effective writing, that’s the instructions from a fireworks package. Similarly, when you want a good ruckus, ask a bunch of paddlers whether they prefer wool or polartec / polypropelene. Both sides have ardent supporters and neither can persuade the other.

I think that means you have two pretty good materials that work for lots of paddlers. I’ve had pretty good results with both, but prefer the synthetics.

As to your question, I really think the weave or construction of the material is key. I believe in the “wet suit” effect once the material inside the shell is wet. I’ve been for swims with the ice slabs in my old paddling gear (not dry suit) and it wasn’t that bad. The shell kept masses of cold water from circulating directly onto my skin, so it was not ice-water, shock, cold. But it did get cold and I don’t think I would have lasted a half hour, at least not happily. So, if it is going to work like a wet suit, you have to have some pile thickness between the outside of the suit and your skin. A stout wool knit would do it, as would, I think, polartec fleece.

Anybody crazy enough to want to test it out with different, wet, insulating materials, I’ll listen with interest to your results. Meanwhile, the fuse is lit, and this could go on for a bit.


Was having the exact same problem
as Ridley. NRS Hydroskin long sleeve top and bottom under dry suit solved problem. Nothing else needed for temps in low to mid 40`s. Temps get colder will go with a light weight wool over the Hydroskin. Now have to figure out whether to go with pogies, gloves or mitts for my hands.

What works for me…,

– Last Updated: Dec-03-09 7:22 AM EST –

I should note that I am particularly vigilent about getting totally sweated up in the layers under my dry suit, but for different reasons than the usual. I wear the suit into and thru much warmer temps than most, to the point that for much of the year I have to change into a fresh layer for my upper body at break.

Re wicking moisture away from my skin... the only materials I have found that do it completely effectively are Cool-Max stuff or one heck-only-knows what Hind top I found. For warmth, The best layers over that for me are polartec, something like a thicker Power Strech top or in really cold weather a 200 wt old top. They can get a bit damp, but if I am not able to switch out to a dry top the loft of the polartec seems to keep me from feeling wet and chilled.

Wool should also work to keep you warm when wet, though it might feel a little less so if you hit cold water and your suit has aged enough that it has lost its water resistent outer coating.(That is one reason it's worth using the stuff that renews it.) Unfortunately there isn't any type of wool I have found that doesn't itch if it is next to my skin, and if I have the base layer of CoolMax anyway the polartec works fine and I have a lot of it.

Bottom line, different things tend to work for different people. And the layer that wicks moisture away from your skin may not be the same one that keeps you warm. So you may match up with someone here, or may have some completely different solution that works for you. Just hit some good sales, try a top or bottom or some different materials, and find out what works best for you.

Is your dry suit breathable?
If it’s one of the non-breathable, coated-Nylon variety, you will never stay dry in it.

That said, I’ve had good luck with both wool and synthetics under my dry suit. It’s more a personal preference than anything else.

You’re correct
There is no answer to the problem you describe. No drysuit breathes like a cotton T-shirt in the gym. One practice I can pass along is to start your paddles out slowly and let your body heat up gradually. If you charge out of the starting gate you will sweat like a pig. You’ll see a noticeable difference when you paddle easy for 20 minutes or so. Also removing your hat for a few minutes can cool you down if you start to overheat.

Don’t forget you have a spray skirt tunnel and PFD blocking the greatest heat areas. The only times I am not damp under the Gortex suit is when I intentionally under-dress for the water on safe inland waterway paddles etc.

Online summary anywhere?
I was wondering if there was perhaps an authoritative article posted anywhere summarizing the various base layers? I am for example, curious how “smartwool” differs from wool. Thanks.

Smartwool is just a brand name
Smartwool is just wool, although super high-quality merino. They have some proprietary blends to help with wicking, but in my experience, at the cost of warmth.

The trapped layer of water does not

– Last Updated: Dec-16-09 6:28 PM EST –

insulate in any way. That water conducts heat much better than an equivalent airspace. Having used a wetsuit in the ancient past, I know that water layer feels good, but the simplest consideration of the physics of heat transfer shows that the "trapped warm layer" is a suburban myth.

I find that "polypro" (meaning polyester treated to "wick") is inferior to polypropelene as a base layer, because in the usually humid drysuit environment, the "polypro" wicking garment does not wick, and becomes sodden. The coatings often used on wicking fabrics give the fiber surface a strong affinity for water.

Polypropelene has no surface affinity for water whatsoever, and unlike Nylon and polyester, polypropelene does not absorb water into its fibers AT ALL.

Wicking fabrics have achieved their reputation in more open-air environments where water density and temperature gradients cause water to move outward to replace water that has evaporated. Such conditions exist only weakly under a drysuit, if at all.

A wickiing fabric, if not exposed to drier air, is going to become sodden. Its only advantages over cotton are that polyester does not absorb much water into the fibers, and polyester does not become limp when the fibers are saturated.

$149 ?
I think I’ll stick with my plan of picking up merino shirts at the local thrift shop for $3-$6 each.

pigs don’t sweat
at least that is what I heard

I wear
polypropelene long underwear, a polartec fleece liner and a couple of pairs of wool socks. No way around it - if you paddle hard, sweat is going to build up inside the suit. I find that I stay warm as long as I keep moving - even after a swim. The times I do tend to get a chill is when I stop for an extended period of time like at the lunch break. I’m usually one of the first ones back in the boat to get the furnace running again.