Have no idea what its purpose is, but the pitting and the bolt backing out without its nut (or is that other bolt missing?) makes me hope it's not a critical piece of componentry, especially with that gap at the base where it looks like there might be some bearings.
So, what is it?
Reckon it is a Harken furler with a missing retainer bolt. Remove the other and see how well the furler works. Been there...
Carry spare bolts and we run a piece of electrical tape around and over the bolts to ensure they don't back out again.
Yep, Justin got it. Welcome back Cotter...I mean Carliane. (Great video clip - post it here!)
With SHF coming up, I decided to check the torque tube screws in the furler. They had been tight with a couple layers of black tape wrapped around the tube, and I noticed the tape was getting loose. How one screw backed out and escaped under the tape is a mystery and a second was clearly on its way. No screws, no rollie-rollie. The scaly stuff is just glue from the tape, and more screws are on order.
Lost screws from Harken furlers is the stuff of stories around here - so check those screws!
Tape around the screws: why didn't I think of that? Duh
Silicone "Rescue Tape" (as sold at the boat shows and at Whale Point Hardware) works even better. Self amalgimating, tougher than electrical tape, and no sticky residue.
Personally, I'm a fan of Gorilla tape for stick-to-it-ness though I love Rescue Tape for areas where you want a cleaner appearance because, as we all know, it's really all about how pretty the boat looks And Loctite for those bolts, just to be safe!
I'm planning to put together a highlight reel of Tubbataha Reef. AMAZING place. Hope to post that soon!