These are some clam cleat variations that match some of the cleats on my boat.

Printing Recommendations:
The cleat ribs are angled 45°. If the print is angled 45° so that the cleat ribs are horizontal (parallel to the print bed), the ribs will be printed smooth which will reduce wear on any ropes.

Variations:

• Screws - is designed to be attached with screws and has countersunk holes to fit #8 or #10 flat head screws
• Bolts - is designed to be attached with bolts and has countersunk areas to fit a 3/8" nut socket (which should fit a 3/16" bolt)
• Rope - is designed to be tied to a rope (with a stop knot or a loop knot). The stop knot configuration works best with 5mm or 6mm rope and a figure-8 knot. Smaller rope sizes may require a larger knot to keep from slipping through the hole in the cleat.

Disclaimers:
There is no load rating for these due to print quality and other issues. My practically solid prints of these seem plenty strong for my uses. Use at your own risk. I wouldn't use these for critical situations. Buy a nice set of rated clam cleats for critical applications.