Cleat on mast below winch

My 1978 FS has a plastic?/nylon? cleat mounted on the mast, in the sail track, right below the winch assembly. It runs vertically and does a great job at grabbing a flapping jib sheet when I tack in strong wind and holding it for me so I have to jump forward and release it while I hope the tiller stays relatively straight.

Does anyone else have this? Is this a factory install or was it done afterwards? What is it for, docking? There is also a screw that seems to be in there hold the bar into which the cleat's mounting screws are screwed.

Any input would be great, thanks.

"If the sea did wild or wicked things, it was because she could not help them." - Hemmingway

The cleat can be used for basically nothing, and you are right, it can catch a flapping jib sheet.

The metal slug that it screws into, serves to keep the pin for the mast hinge from sliding up the track as you raise the mast. The slug must be in place to use the mast hinge.

I took off the cleat and put the slug back in, bottoming the screw in the sail track, so the slug can't slide. You will notice that when the mast is up, the bottom of the slug sits nearly in contact with the top of the pin on the mast hinge.

Phil Scheetz
FS 4086