Mast mounted winch

[Startacker]

We were sailing in 15-knot winds on my Ericson 30. While tightening the Genoa halyard with the port side mast winch it started to come out of the mast. We quickly tied off the halyard to a cleat and were able to remove the winch from the mast. Upon inspection we found the bolts holding the winch to the mast were only tapped into the aluminum on the mast with no back support.
I want to install 2 - 3/16” aluminum plates, one on each side. Then use ¼” stainless steel all thread to sandwich the mast in between. Then I would tap the bolts into the plate and the mast and reinstall the winches.
I am thinking this would be an adequate base for the winches and actually strengthen the mast. Another sailor told me it would actually weaken the mast at that point. Any suggestions would be appreciated.

 

[Geoff Johnson]

I installed a winch on an O'Day 23 mast using by making a Marine Tex "sandwich". Because it was a deck stepped mast, the winch was located about four feet above the lower end, which made things much easier. First, I put a square of Saran wrap inside the mast (to prevent sticking), using the mast as a mold, and put a large pile of Marine Tex on the Saran wrap. I pressed a backing plate of 1/4" aluminum into the Marine Tex and let it cure. Using this aluminum/Marine Tex sandwich as the male mold, I put it on a bench, curved side up and covered it with Saran wrap. I placed Marine Tex on the curved side making sure that aluminum backing plate and the upper (flattened) surface of the uncured Marine tex were parallel. On curing, both halves were then power sanded to the diameter of the winch, drilled and the inner half was tapped to accept the winch bolts (Marine tex is easy to tap). The male mold part was then positioned in the horizontal mast and the winch, female mold/winch pad, and inner male mold were all bolted together through the mast wall. The end result was enormously strong and supported the mast wall between the two halves of the mold. Of course if your mast is keel stepped or still on the boat then you will have to use another method. However, the method you describe seems like it would collapse the mast like a vise.

 

[mdgann]

mast winch

This sounds like an ideal opportunity to change the mast winch to a cabin top setup and lead the halyards to the cockpit. I did this during the winter last year and enjoyed the additonal flexibility it provided in adjustment and the safety. This has to be the best modification that I have made.

 

[Startacker]

Mast Winch

Filling in the holes and running all the lines back to the cockpit sounds like the perfect answer. Thank you for such sound advice. That is something I was wanting to do for awhile and now is the perfect opportunity.

 

[mdgann]

I would be hesitant to try and have the holes filled by welding. The Heating would change the character of the metal in the local area and set up fatigue at specific points. You could put aluminum rivets in the holes or JBweld sanded off if the holes bother you. I don't think you will have any structural weakness from them as they have been there for awhile without problems.