Please mark NSFW.  I'm pretty sure you wouldn't want people peering over at your screen while reading the OP.

I was blasted out of my Cobra Tourer (which is 15' and very heavy) by a GW about 2 years ago off Pescadero - you can search for my post on this forum.  From the bite marks it was estimated to be 10-12', and it hit hard enough to launch me in the water and flip the kayak over.  I climbed on the overturned kayak and remained there like that for quite a while, until my buddy paddled over, and until my heart rate calmed down.  Then I had to get back in the water and flip the boat over - which I did in record time!  I got the nerve to go back out fishing 3 months later in the same area, and was buzzed by an even larger GW - swam alongside of me w/ dorsal fin out of water, spun around bow and i poked him in the back with my rod tip.  I don't kayak fish on the coast here anymore, I fish off boats.