I was thinking the cleats on the front crossbar for the jib that the Prindle 16 has and the 18 doesn't. It sounds like maybe you need the one on the back crossbar that the main sail blocks go through. I may just go get them all from him I all ready relieved him of all his standing rigging including several blocks and shackles. even a really nice quick clip one. I thought the the rigging itself was shot and was gonna toss it but after looking closer it was just the coating on the cables that made them look shot the cables them selves look all right. So I have 2 side stay cables and a Forestay cable and 4 trap lines for a Prindle 16 plus all the extra blocks and shackles for about $10. Plus I bought his Cat Box for $50. I didn't take any of the cleats that were attached to the boat though. They should still be there.