What is this?

[Kiteboarderken]

Hi, found this in Dominican Republic a few days ago. No tape measure on me but the larger part is about 4" in diameter. I can't locate anything similar doing a Google photo search. Thanks for any info on identification and age!
Adding some more pics with measurements. The smaller hole looks like a bolt went all the way through and the larger one has a pin that allowed easy and quick opening like to deploy something. No markings at all nor serial/part numbers.

 

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[Blackfoot58]

I’d guess it to be an item to hold 2 different-diameter poles parallel.
It would cap one end and a similar piece would cap the other end. Maybe for sail rigging?
I’m just stabbing at it based on appearance. Hopefully someone will have a better response.