Mast rot. need advice. can it be fixed?

[captianjuan]

Hey all,
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.
fair seas,

[Fore and Aft]

CaptainJuan a friend with an unstayed timber mast had the same problem. He replaced 8 feet with a solid block of wood and used a 3 foot long V scarf. Where the scarf was he also wrapped with 450gm double bias cloth. It's held up well on his 35 foot yacht.
Cheers

[Bowdrie]

It was hard for me to see, but is the mast sitting inside a welded-up "socket" type of step?
From the pic is the rot only on that one face?
How important will the mizzen be to you in order to get to Mexico?

[captianjuan]

the rot starts above the base but inside the SS sleeve. sleeve is only a few inches high. it goes up about a foot. its only on one face.

[Orion Jim]

Join the Woodenboat forum http://forum.woodenboat.com/ and pose this question to those who own and maintain wooden boats by choice. The necessary repair will not be for the fainthearted and there can be no compromise as a catastrophic failure could cost a life…or lives.

[Bowdrie]

Originally Posted by captianjuan

the rot starts above the base but inside the SS sleeve. sleeve is only a few inches high. it goes up about a foot. its only on one face.

As the rot is inside the sleeve trying to sister that face section probably won't do much to make the mast suitable for much strain in a fore-an-aft direction.
Can you put a piece of wood, (even a length of 2x6,) against that face and secure it with a "Band-it" tool?
Then slack the rigging a little bit and sail to Mexico without using that mast?
I'm assuming that pulling the stick and laying it on deck for the trip probably won't happen.
You've got 3 good sides, (hopefully,) and without a press of sail it should be ok.
Even ~2 turns to loosen the turnbuckles will relieve a huge amount of compression loading while still keeping it in place.
Just thought, if there is a "triatic" stay from the mainmast head to the mizzen head any forward loading of the mainmast will translate into compression loading of the forward face of the mizzen/tension on aft face.

[psk125]

Hard to tell the dimensions from the picture. If it's spruce, I'd be tempted to find some 2x D-fir lumber and sister it up on all four sides on the outside, from the base to maybe 3' up. Screw & glue everything together snugly, including into the good parts of the mast. Maybe add some hefty SS hose clamps on the outside too. You can make it look pretty when you get to Mexico.

[fourlyons]

Originally Posted by captianjuan

Hey all,

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.

fair seas,

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.



Sent from my Z5157V using Cruisers Sailing Forum mobile app