Surfing Waves

I'm gonna be making a longish drive like 2 hours highway in a week, and never tied anything to the roof in my life i just got a longboard, the other ones fit in the suv so i didnt even have to trouble with a tiedown haha

I have two tie downs, those simple ones that form a loop and latches closed

Whats a good way to put them on a longboard on top of my SUV. Its an explorer with a luggage rack. I have some padding to put around the rack to help protect the board a bit.
I just dont know how to securely tie down a board..i need a tutorial Id feel horrible injuring the driver behind me if it went flying lol

i use a bunjee style chord (its thick black rubber and use 4 of them - should be able to buy the same thing from home depot/auto zone) I just did a 1100 mile round trip and my board didnt budge an inch on the roof.

All you need to make sure is the board wont slide forwards if you brake hard for any reason, stick some rubber grips on top of the roof rack bars so it wont slide. Then use bunjee cord to tie down =] Job should be a good one