It's probably no secret here I am a novice kayaker. To qualify that a bit, I do mostly flat water kayaking, in season, and have been doing it for a couple of years. I do own a spray skirt but have never used it and have never rolled my kayak.
I got to thinking about doing cold weather kayaking so I did a little research on what type of gear I would need to do this safely. The proper wear for cold weather garb falls into two categories. There is your basic wet suit and something called a dry suit. While a wet suit can be had for around $100, a dry suit starts at about $400.
Now being a cheap bastard, I was leaning towards the wet suit. However, since making the wrong decision could lead to a certain icy death, I thought i'd turn to a co-worker who is a certified dive instructor and has spent many hours in cold water teaching idiots how to deal with the briny deep. Here is his response, which I believe is the best scientific discussion of cold weather gear for kayaking that I have ever read.
Really tough question to answer without knowing more info. What kind of kayaking do you do. What temp do you do it in? 60 water? 40deg water? Freezing conditions like now?
You lose heat in several ways. I'm going to simplify this from true thermodynamics, so we'll consider two ways. Think of a cool day outside wearing no shirt. Your body warms the air directly next to your body. If the wind is blowing, that warm air gets blown away quickly, so your body has to reheat the air. This makes you cold. If the air is still, your body is more comfortable. But then the air transfers heat to the surrounding air, and things cool off. That is the thermal conductivity of air. The cooler the outside air, the cooler you will feel.
A windbreaker helps by stopping then wind. It doesn't do much for the thermal conductivity of air, but it stops the wind from blowing the warm air way. A coarse wool sweater may not stop the wind as much, but it helps with the second way, providing insulation so that the thermal conductivity is much better. The best is a windbreaker over a wool sweater. The wind is stopped with the windbreaker, and the sweater helps the thermal conductivity.
With water, everything is sped up. It pulls the heat away so much faster.
With a wet suit, you will get water next to your skin. So there is some "wind" that gets through the "windbreaker". However, it slows the water movement, and keeps the now warmer water next to you, so you stay warmer. The thickness of the wet suit slows the thermal conductivity.
A dry suit keeps all water away from your body. So you don't get wet. Also, the outside of the suit is usually a lot "slicker" so it doesn't hold a lot of extra water for evaporative cooling. Much better all around.
But here's the rub with a wet suit. When diving, your wet suit gets soaked. But your ok. The water temp is similar around you. But then you get out. The evaporative cooling pulls the heat away from your body really fast. I have been diving in a 7mm suit in 40deg water. I'm cold, but not too bad. I get out of the water into a 60deg air temp with a faint breeze. I'm suddenly very cold. Much colder then in the water. I would often keep students in the water when teaching to avoid that. You can limit the evaporative cooling with a windbreaker over the wet-suit, but it still cools you down.
Now, for a couple of specifics for kayaking.
You're not usually submerged. So you may not get that layer of water next to your skin. That will help a lot. You may get splashed, (a lot maybe), so you will get some cooling. However, you can put jackets and such over the wet-suit for thermal protection. The also helps with kayaking in variable weather. You can adjust your jackets and such for controlling your temp. If warm, shed a layer, if cool, add.
It all goes out the window if you go under, or drenched from the water.. Your jackets get soaked, and unless they are wool or a smart layer, you loose all thermal protection from your jackets. Your wet suit will protect you from the sudden burst of water and will help keep you warm (especially with a wind-breaker helping keep the wind from helping to evaporate water from your wet-suit.)
With a dry-suit. If you go under or soaked, you don't care. You won't get wet. Your thermals are all inside, so they stay dry. Much better. However, you have a harder time to shed layers or deal with getting too hot or cold. You can't easily add/remove layers. And if you open the dry-suit to change thermals, you really have to be careful not to fall in.
From my experience with kayaking, here would be my recommendations...
- If you are doing casual kayaking, little to no whitewater, generally very stable in the water, and you are in 60deg water or spring/fall conditions, go with the wet-suit. Throw some fleece on as needed to compensate. If you go in the water, take a couple of minutes to towel off and such.
- If you are doing more extreme kayaking, lots of whitewater, or really cold temps like now, you go into the water a lot, or get drenched regularly go with the dry-suit. Bring some layers, but pull off to the side and get stable before cracking that dry-suit to change clothes.