Share 'locks for sliding main hatches'

G,day all, I am at a loss as to how to lock/ secure the main hatches, actually all the hatches now that I think of it.I read somewhere that a bloke secured his front hatches with a bit of chain fixed inside the the main hatch with the other end of the short piece of chain going to a saddle with a lock on the underside of the hatch.This allows you to get a hand in to open the lock but restricts yo…