What are typical hull speeds for say a 17 and a 19 foot kayak?

I know that the longer the kayak the greater the hull speed. What I am curious about is am I able to paddle hard enough to come close to the hull speed?

At what length of boat can I physicaly no longer paddle hard enough to aproach the hull speed of that boat?

I am looking for ball park figures. I realize that there are a lot of assumptions need to be made.

Any takers out there?

Matthew