New Andersen WD hitch

BenK wrote:
...To me, shackles are for a joint that will be disconnected often enough
to warrant that. In this case, I'd have it bolted in a sandwich of
plates and/or tubes welded onto those plates.

I worked in medium to heavy industry (large electrical and irrigation utility) for over 32 years and never ever saw a factory installation that bolted a chain as you described. The only ways I saw chains being fastened was permanently to a hole using various kinds of split links, two piece links, etc. or by using shackles or hooks.

Bolting a chain down would create additional stress on the connection, how much depending on the angle the chain was being pulled since the chain would be pulling off center from the center of the plate. Also, the spacers and/or tubes you mention would add unnecessary cost to the hitch because of additional materials and labor. Shackles would allow movement that would prevent stressing the connection other than the direct pull. They also allow for easier adjustment of chain length.

I've seen shackles used in similar situations, sometimes temporary, sometimes permanent. A shackle that had an opening closer to the thickness of the plate might have been more appropriate but only if the chain would still fit. It may have been sized as large as it is to assure adequate strength.