Rooftop kayak transporting

[Jorgie]

Up until this weekend I had transported my kayak on the roof of my car. I would put my kayak cockpit-down on to foam blocks, then strap through the grab loops to the frame of my car, and one strap around the mid section of my kayak and through my doors. I knew I was tempting fate by putting that much strain on the grab loops, and sure enough, the bow one broke this weekend.

My question is, how do you transport your kayak on the roof of your car? I don't want to buy a roof rack or a trailer. My thought is buying two heavier-duty ratcheting straps and going through the doors/windows. I'm not sure if this would be secure enough though. My kayak does fit in my trunk with the back seat folded down, but a good four feet of the kayak sticks out so I would like to avoid that on longer trips.