generic use
If I was just making this for my personal use I would be likely to agree with you and just use windproof material, since I’m usually dressed for conditions anyway either with goretex or something like hydroskins or other material that will keep me warm if damp provided I can cut the wind with a shell over it. And I would tailor it to fit myself instead of having it big and baggie like the “one size fits all” Kokatat. But I look on the cag as a piece of general emergency gear that I would want to be able to sip onto a chilled, tired and/or incapacitated fellow paddler if need be, someone that might not have the right clothing or at least what would be sufficient for the circumstances.
Something I’ve added to my paddling safety kit is a neoprene headwarmer helmet, after watching an excellent extended video documenting studies of people in extended immersion scenarios (conducted in controlled situations with rescue crews at hand and medical supervision.) It was VERY enlightening to see how quickly real people became disabled and distressed in cool to downright frigid water but one of the results of the study was that people wearing warm headgear retained physical and mental competence far longer than those who were bareheaded. In fact in one example a guy wearing street clothes and an insulated cap held up better and longer in 50 degree water than a bareheaded guy in a wetsuit.
Though I’ve always been aware of the seriousness of heat loss above the neck (when I was a backpacking instructor and guide I always carried spare hats and warm scarves that I would force upon any students exhibiting early signs of hypothermia) I was really surprised at how affective a warm hat proved to be in immersion events. In fact I might experiment with using stretch fleece as a border around the face opening in the cag hood or even a lining, as with the handwarmer kangaroo pocket.
Another option I had considered for a cag/tuilik is bees-waxed cotton, like what the Brits use for rainwear. I bought several yards of it in brown a few years ago, thinking I would make a “trad” looking anorak to use with my Greenland replica SOF and wood GP. Likely be rather bulky and beastly hot, though - I don’t think waxed cotton breathes much at all.
Waxed cotton
I bet would make awesome pogies, especially with a nice fleece inner lining:) Might be a little bulky for something the size of a cag, although the hipsters might start buying them for their Starbucks runs.
I usually find I can keep myself pretty comfortable by keeping a good assortment of gloves, pogies, and head wear on hand. Even if I'm going bare headed I keep a light neoprene hood tucked in my life jacket in case of a swim. Under the drsuit I also try to wear a little too much, so when I start off I'm hot, but when I start sweating and my layers get damp I'm okay. I like to avoid long stops (unless it's really nice out) to avoid cooling down then having to start back up.
A silnylon version
That is the material, or exactly like, used in the original ones by Valley. The kind that I said above I knew two people who had but both found it was not all that useable because it was too hot once they were paddling. Valley stopped making them so these two could not have been alone.
jacket
I like the Kokatat full zip jacket. I can wear it any where and if in boat put over all my gear and zip it up easily.
https://kokatat.com/product/gore-tex-full-zip-jacket-pjupfz
hat
Great hat made of gortex. Floats, stays on head with adjustable bungees, good for visibility, good protection. Also I wear it winter and summer and it is comfortable. You can also bend rim different ways and it stays that shape. You can bend sides up or down and front up or down for more protection or visibility. It is worth the price.
DTP has a breathable cagoule
I was just ordering something from Duluth Trading Post and see that they are selling a lightweight breathable Paratex (?) cagoule (though they are calling it a “poncho”) for $64:
http://women.duluthtrading.com/store/womens/womens-gifts-womens-gear/64809.aspx?processor=content
Since it’s designed to be big enough to fit over a backpack, I’m guessing it would probably fit over a PFD. Not a great rescue color, though, in olive green only. And no handwarmer pocket (though that would be an easy modification). But the price is right.
even cheaper
Searching on “Snugpak poncho” I found the same cagoule on multiple sites, as cheap as $36:
http://www.amazon.com/SnugPak-92285-Snugpak-Patrol-Poncho/dp/B001B8FYBA/ref=pd_sim_468_3?ie=UTF8&psc=1&refRID=5Y6MFVC968QFANMSZ90Q
Lots of 5-star reviews on there for it, including one that says it worked well as rain protection for someone in a wheelchair, so it sounds like the hem might fit over a kayak coaming. Company has a UK website with specs on the Paratex fabric (see link below).
http://www.snugpak.com/outdoor/snugpak/technical-information#tech_1
At 13 ounces the Snugpack is likely slightly heavier than the Kokatat Storm Cag, which I am guessing is around 10 ounces – Kokatat does not post weight but as it is made of 2 oz per square yard fabric and a garment like that takes at least 3 yards, I figured 6 ounces plus the weight of fittings and trim.
Absolutely no doubt that the Kokatat is a superior product but at 1/6th the cost the Snugpak seems like a viable alternative for occasional use. I’ll report back when I get the one I just ordered.