Im not sure what size kayak you are going to be taking along, but how about just tying in through the latch points for your top on the windshield and running it over the yak using something like a truckers knot to pull tension on it, if its a long boat and sitting over the hood run a line through the front grab loop that 90% of kayaks have and down to the tow hooks or shackles on the front bumper if you have em. Or just get an inflatable kayak. Advanced Elements makes several great and durable options with most being less than $500. Does it require you to spend some more cash yes, but that route will also cut down on having to take a chance securing the yak on the roof, and will also improve your fuel economy since carrying anything on the top puts the suck on you MPG's If its a very long trip you may actually end up close to breaking even.
Fortis cadere, cedere non potest
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