Originally Posted by captianjuan
so I am just about to purchase
a boat and discovered rot in the base of the deck stepped mizzen mast. I love the boat. But I don't know what's repairable and what's safe with regards to a wood mast. its soft from just above the 4" high stainless sleeve to about 1.5 feet up. its a sitka spruce, appears to be laminated with a wire tunnel. I was thinking of cutting it and laminating some plates and building a metal sleeve with bolts, possibly doing it in place by drilling a hole in good wood and lifting its weight off the deck and then cut out and rebuild
a new base. Im in Hawaii
now and its not cool to do shipyard here. im an experienced sailor/marine engineer
. I have crossed oceans before. please don't lecture me about the dangers. im looking for ideas about a solid patch that can get me to mexico and then how permanent and worthwhile it would be to to a full repair there vs an aluminum
swap. im thinking of making a laminated sleeve or a metal sleeve and sail it to mexico for shipyard. thanks guys.
Captainjuan this is a simple repair.
The vast majority of force for a stayed spar, particularly at the base, is pure compression. Cut out the soft wood, and epoxy
in what we used to call a "Dutchman" or wood patch. In this case it could be any dry wood you can get, of the same thickness, and maintain grain orientation. Ideally you would scarf the ends for a proper repair. But with three good sides, and since it's so close to the base, scarfing isn't absolutely necessary, square butt joints will work
. Wrap it in biaxial glass if you're concerned about not scarfing.
And yes, if you can extend the sides of the metal base up above the rot and put a number of through bolts clear through you can leave the rot for Mexico.
With a copy of Skene's Yacht Design or the Internet
you can calculate the compressive force on the mast and know how many bolts are needed.
You could also coble together a repair and do the trip without raising any sail on that spar. That would put very little strain on it.
I would really make sure you are correct about the extent of the rot.
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