Events now cater for some or all of prone, SUP and foiling paddleboards. I think there is a fourth class of paddleboard which is similar but different again: canoe-style with a canoe paddle. I would love to have the option to compete canoe-style in paddleboard races like the 12 Towers, King of the Cut, etc. Obviously SUP and prone rules currently prevent it.
I have unlimited prone and SUP (dugout) boards but canoe-style is my preferred method of paddling on both. Either both knees (mainly on the prone) or one knee (sprint canoe style in my dugout). I use a short SUP paddle but with a large blade (over 100 inches).
I like the stability but I also like the stronger contact with the board through my knee(s) that allows a slower cadence but more powerful stroke than stand-up style. The ability to paddle easily - even enjoyably - into the wind is also a big plus for me. On the prone board it is far more comfortable (at least for me) being upright with the paddle rather than right down trying to bury my arms, but it still has a similar feel.
I am also motivated by these guys
My emergency backup paddle for touring is a general purpose boat paddle. One of the reasons for choosing it was in case I get in a situation where I need to knee paddle a long time; I would rather have a short paddle with a straight shaft. The main reason I chose it is that you can get a practically indestructible telescoping boat paddle for about $10 US.
An interesting thought, a new class called KP (knee paddle board). I wanna see this class!
How about C1 paddleboard, to align the name with all the other classes that kneel?
These guys, Wild Water C1, are on both knees
So that would mean that SUP, or paddle boarding would include, prone, standing or kneeling. ie. Any way you like except sitting on your bum (in which case you're a canoe or surf ski or an OC)
If there was a kneeling paddleboard class, what would stop someone entering on a C1 canoe and blitzing the field?