When I first owned my 33, the halyard turning block failed and needed replacement.
Upon attempting to remove the 5 bolts holding the block in place, I found all stainless steel bolts frozen in the aluminum casting. This necessitated removing the collar from the mast to work on extraction of the bolts.
There was sheet rubber (neoprene?) as an interface between the collar and aluminum mast.
Once I successfully replace the halyard turning block, I reinstalled the collar with new neoprene sheet as the interface between the collar and mast.
Under the load of the halyard the collar rotated on the mast. My temporary solution was to run a lasing from the turning block forward to the Sampson post. That was effective but not elegant. The final solution was to install thicker, 3/32” (my best recollection but maybe 1/8”) neoprene.
It seems to me that gluing the collar to the mast with 5200 adhesive sealant may cause future issues when one needs to remove the collar.
I’m happy I shared my plans, and that we can brainstorm solutions. Always good to have a plan for future maintenance.
Two thoughts come to mind about about the challenge of releasing the 5200 for future repair.
There is a product reviewed by Practical Sailor ( HERE ) called Debond Marine Formula that is effective at softening 5200 enough to work it loose. I don’t know how deeply it can penetrate a joint that I’d be creating between Soave’s mast and collar. ( about 2" oval )
I have read that 5200 softens between 140º F and 190ºF I think most Aluminum alloys would be OK under 250ºF. So heat may be an option.
Does anyone have experience with 5200 and aluminum ?
I’ll circle back with Mike Quill also since he’s probably had to work with this exact scenario before. ( the 5200 came from his install instructions ).
Thanks,
Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
The failure may have been caused by the paint on the mast. Shear strength is what you are relying on when you put the 5200 on the fairlead collar ears to keep it from rotating. 5200 has 390psi shear strength on aluminum, meaning that one square inch of the glue placed between two pieces of aluminum it will resist 390 pounds of shear (sliding) force. Some substrates offer considerably less. The 5200 data sheet doesn’t spec shear strength for any paint, but I think a mast freshly painted with two part paints should offer similar shear strength to FRP and that would be about 360psi. So using 5200 between the aluminum fairlead collar and a well painted mast should give you 360psi shear strength. But poor quality, improperly applied, or just plain old paint might offer considerably less.
You’ll put more than 1 sq in of 5200 on each ear - or it will squeeze out to more than that, anyway. So unless you over harden the halyard by a lot, it should hold extremely well on good mast paint. If you over tighten with that big powerful electric winch then something bad is going to happen. In my experience (the PO apparently did just that) having the glue come loose is about the least bad thing you can hope for.