safety chain
 

What is the proper method to attach safety chains to an aluminum trailer?

I would like to replace the existing safety chains on my aluminum trailer. The PO has the chains attached via a bolt & washer. The bolt & washer go through a chain link, and screw into a threaded insert on trailer frame. This doesn't strike me as the most secure method, but i have nothing to back that up with. If you all think it's good enough, I'll leave it be. But I was thinking of a shackle with a clevis pin instead of a threaded bolt would be more secure. If there's a better way to do it, what is it?

I would at least get longer bolts, thread bolt thru, put a big washer, then nut to secure bolt

Loadmaster trailers uses the foremost 1/2" bolt that holds the coupler to the 3" aluminum box section. They ran the 5" bolt horizontal through the coupler, through the aluminum then put the links from the chain over the bolt up inside the hollow 3" tubing and then ran the bolt out the other side of the aluminum and coupler with fine thread locking nut to do the holding.