I hate you --- You put me on a mission to find that gadget! Yes, "padeye" or "pad eye" - just google that and you will find dozens of sources AND all sorts of related info; like: load testing! Design, etc.
Now... If it was me (I am cheap - No! FRUGAL!) I would find a marine supply junk yard and re-cycle one. In the early 1980's I lived in Marina Del Ray (are you close to that in CA?) and they had a number of places to buy stuff new or used around there and in the ship yards around San Pedro & Long Beach Harbor.