My 12 foot canoe only weighs 34 pounds and is easy to put onto the truck, but the kayak must be more like 45 or 50 pounds. Our 16 foot molded plastic canoe desined for a full spray skirt, must weigh 80 pounds and its 34 inches wide. We haven't really been able to us it and its flip up seats because my wife couldn't pick up half of it.
Finally I cut two 2x4 to fit the curve of the roof on my old forerunner. I laid them sideways across the top and screwed them to the truck with special high strength spline drive screws through the roof of the truck in 6 places. They are sealed down in caulk. 2 8' 2x4s, one on each side screw to those pieces and create a frame. Then posts and cradles are screwd to i all to hold the three difference boats, and finally there is a cross piece above the largest one that sticks out over the rear of the truck and it has a 2 part block and tackle. The tackle snaps to a rope 3 feet behind the front of the caoe and pulling on the rope lifts the bow and pulls it up and starts it onto the cradle. Then I move it to a rope 3 feet from the stern and pull the rope again and the entire canoe is lifted up and onto the cradle no problem and there are 18 high guides on the side so it can't blow or fall out of the cradle.
So this has allowed us to easily load and unload the Canoe and Saturday we're taking it a local hot springs heated lake thats warm and we're gonna take it out and jump over board and swim. I'm throwing in my swim fins and goggles and snorkel.