17 knots sounds far fetched! You could just about ski behind it @ that speed -
I've had mine to 8.5 kts according to the GPS - but that was running before a very strong northerly on the way back from Sydney Harbour a few days after new years - with a largeish swell pushing us along. Far too much sail up, far too inexperienced - but other than a broken hand on a crew mate, far too much fun! To the crew mates great credit, he kept fetching refreshments, in spite of his obvious discomfort.
Althought they're a heavy little boat (and not great performers in club racing) they're a solid option off the coast!