C-Forum

Technically it's "Surfing" and "Touring" but I prefer to call it Paddleskiing (Human Powered Water Skiing).
The boat is Wavewalk's W1, which is not exactly a C although you can kneel in it and paddle with a canoe paddle. It's also possible to paddle standing and use an extra long canoe paddle.
Anyway, it's certainly not a K

putting a sadle in there?

Actually there's already a built-in saddle inside
See: http://www.wavewalk.com/W%20boat%201st%20model.html