Longboard lock?

I am going to start taking my longboard out on small days and. If waves are good, I want to lock it up. Problem is, it won't fit in my SUV and am afraid of it getting stolen, it's a sweet board.
Do you guys have an idea to locking a longboard on Thule surf racks? I went out and bough a 6ft steel cable and lock, will that do the trick?
Sorry, out of my realm, let me know how you lock your longboard to your surf racks.
Do you guys have an idea to locking a longboard on Thule surf racks? I went out and bough a 6ft steel cable and lock, will that do the trick?
Sorry, out of my realm, let me know how you lock your longboard to your surf racks.