Matt Langenfeld wrote:

looking at his website, I see some plastic ones attached to a surf rider.

Just looked there and don't see what you're referring to. There's a
picture of a sit-on-top with flared hull shape with a caption that says it
has built-in 'sponsons' and several pictures of kayaks with the inflatable
yellow nylon Sea Wing sponsons; plus some of a canoe with larger inflatable
sponsons. Here's the ordering information:
"Sea Wings Sponsons
All sponsons are 40" X 6" in diameter for any kayak, double or single, due
to relative buoyancy leverage, regardless of kayak size. All necessary
hardware, straps, instructions etc. included with each pair. They inflate
in 6 puffs each.
They roll up together and stow compactly, 8" X 3" in diameter. The 200
denier are each under half a pound. The 400 (twice the thickness of the
nylon, double the resistance to abrasion), weigh only 3 ounces more than
the 200.

In US Dollars: (Including Expresspost and Insurance) Type of Material
Color Cost Expresspost
200 Nylon/Urethane Deep Yellow $98 $8= $106 US total
400 Nylon/Urethane Deep Blue $119 $8= $127 US total"

The lighter yellow ones look just like what I remember using at the sea
kayak symposium. I don't see any rigid plastic sponsons for sale at his site.

Peter wrote:

Matt Langenfeld wrote:

Tim,

What's you view on the auto-inflate type of sponsoon that only comes
out during an emergency vs your which are "inflated" all the time?



Where did you get that impression?
I used Tim's original Sea Wing sponsons in a sea kayak symposium
rescue class over 10 years ago. Only some attachment clips were
pre-installed on the kayak. We deliberately capsized/exited and then
attached the sponsons and inflated them. Then we reentered, pumped
out the cockpit, and finally deflated and removed the sponsons. The
process was pretty similar to the use of paddlefloats which were also
used in the class along with assorted types of assisted rescue.
Seems that what he's promoting more recently to the Coast Guard is the
auto-inflate type of device (the ones I used were only manually
inflated).