: Just wondering because I keep washing the car
: down after I come back and I'm wondering if I need to :)

Fresh water in such short supply by you? Or is it a lack of time?

Salt will eat up cars, but usually the parts that go are on the bottom of the car, where salt can splash up and pool in welds and seams. Roofs are painted and get rinsed with evening dew and every rain. Not much chance of a few drops of salty water staying on your roof for long. Once you get the kayak secured, and hit over 30 mph any fluid on the roof is going to blow off. Any residue, whether it be salt or just mud, is going to be trivial.

You should wash down your kayak after use. Might as well get out a garden hose and take care of rinsing boat and cartop at the same time. Then drive around the block to dry it before putting the boat away. Or, head for a rainstorm :)

PGJ