safety chain

[draglink]

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

[RidgeRunner]

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.