Summary

For boats with halyards on the lower sides of the masts where the jib sheets can get tangled the Cleat Guard blocks the "open" end of the cleat allowing the sheet to pass over without getting tangled.
The specific cleat is was modeled on is the Allen A-281 that measures 150mm long with the tips of the cleat standing 40mm from the surface of the mast.

Print 2 per set and join them with 4mm shock cord. I had very good results with TPU with 3mm walls and cross hatch fill using a 0.6mm nozzle but a 0.4 should be fine. I used TPU to save scratching the surface of the mast but the print comes out just as well with PETG. Both materials are UV resistant.
Printed using the angled side as the base and no support.