The search tool is your friend. Check out the following threads with "roof rack" in the title: PriusChat Forums - Search Results Good luck.
The photo in my avatar shows what you want. There are more here and here. It works great for carrying my 2 kayaks. Refer to the User-Guide for details. .
Does your kayak in the right-side-up position tend to try to lift-off??? Would not matter at low speeds, but I have driven our Mazda MPV minivan van or the Camry at 70-75 mph with the kayak on top for quite a few miles at a time. I thought if I have it like you have it, the boat may be putting too much upward force on the rack. I carry mine upside-down - the nose seems to follow the car's aerodynamic airflow this way and does not create that much draft at all, and what it creates it is pushing down, like a giant spoiler on the roof -... Have not tried on the Prius yet - not that I would go 70 mph with the boat over the Prius... I still need to get a set of supports that would transform my Yakima rack from the Camry roof-line to the Prius'...
No. 70 MPH in the rain with both right-side-up, neither with a cover, were any problem at all... other then dropping the efficiency down to 36 MPG. .
