Adding a padeye or strap to mast

[Seattle Scott]

to hang a spin pole topping lift block from. Dont know anything about rivits. Was planning to drill and tap ss screws and I assume the padeye or strap with be ss. Mast is 20 years young, aluminum, and shows paint bubbles and corrosion where all other ss fitings are affixed. Boat is 37 ft, spin pole is 4" by 17'. Question 1: Should I go with a four-screw padeye or is a two-screw strap (eyestrap?)sufficient? Questions 2 and 3: What, if anything, do I use to minimize the SS and aluminum contact and do I put something on the screw threads either to avoid seizing or to guarantee seizing or that they won't back out?

 

[Steve O.]

neither

I would use a 3' track with a traveling ring car.

 

[Brion Toss]

It depends

Hello,A strapeye is usually sufficient, and a good thing as you'd need a custom-curved padeye to fit the mast. With the strapeye you'll want to rivet a thin piece of UHMW or the like to the mast, so the block doesn't clatter away. Alternatively you could install an internal sheave. Clatter-free, and it leads inside, out of the way. There'll be a foul lead out when the pole is athwartships, but loads are lowest there, and a good block will be radiused on the sides of the mortise.As for the galvanic action you are seeing, it is one of the most annoying things that alleged riggers can perpetrate, and utterly preventable. Our favorite fastener isolator is Tef-Gel. A little of it goes a very long ways, and it resists long-term water intrusion better than any other product we've tried (like anhydrous lanolin, Never Seize, Durolac, Lanacote, etc.). For larger surfaces, we use UHMW tape. Mylar also works, as does cutting up a Teflon cutting board, available at camping stores. Hell, peanut butter is probably better than nothing, but nothing is what too many boats have under their hardware.Fair leads,Brion Toss

 

[Garry @ S/V TASHTEGO]

SS-AL isolation

Tef Gel is excellent. I bought a small jar a couple of years ago and the amount you use on a machine screw is so small that I think it will get passed on to my grandchildren. To insulate the fitting from the mast use a piece from a plastic milk or water jug cut to fit the shape of the stainless fitting. You can cut the stuff with scissors and it will last forever sheltered from sunlight by the fitting.

 

[Seattle Scott]

Thanks Brion and Gary

I'll go with Tef Gel and a strap. If I went internal that would require cutting a hole, so I will leave that for when the mast is down. Brion, my wife gave me your Rigger's Apprentice, which I took on a cross county flight with some string to prefect my knotting. Well the kid across from me learned a bunch of knots. Me, well if you ever come out with the Rigger's Appretice's Stupid Friend, put me on the mailing list. Steve, I am working on the topping lift set up, not the pole end mast track fitting