Questions on repairing a rotted mast support

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Questions on repairing a rotted mast support

Postby suthe245 » Mon Jun 29, 2020 10:11 am

I just bought an old rebel 16 and it turns out the wood that supports the mast has completely rotted away. There is a screw in deck plate close enough where I should be able to replace the wood and fiberglass it in. It looks like it was originally just a 2x4 that was fiberglassed in but I don't know for sure. I have done some minor fiberglass work in the past but nothing like this. Im just wondering what the best way to go about this repair is. The first picture is at the bottom where the wood has rotted and the second picture is the top. Any help will be appreciated!

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suthe245
 
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Joined: Mon Jun 29, 2020 9:45 am

Re: Questions on repairing a rotted mast support

Postby GreenLake » Mon Jun 29, 2020 1:14 pm

Frankly, I am a bit unsure what your photos are showing. The bottom one, I don't even have an idea of the scale. The top one, my best guess is that we are looking upside down. It seems to show a fiberglass collar (or partial collar) for the wooden mast support which seems to have rotted very thoroughly. I assume it would have extended in what is the "up" direction of the photo as presented and presumably rested on something ("above" of what we can see). Is that correct? (Is that "something" the one shown in the second photo?). What is the distance between the two? Or how long was that post?

Fiberglass work is in some sense dead simple. You get your resin and glass. You mix the resin per instruction, cut the glass into manageable shapes, put in place in layers and make sure each layer is wetted out. The skill comes in working neatly with this somewhat messy material including no using more resin than needed to keep the ration of glass to resin high.

I prefer to use epoxy resins for my repairs, and for consistency, always use the same supplier (SystemThree in my case). They publish an online publication the call "Epoxy Book" that is full of useful instructions. The key for working with epoxy is getting the ratio between resin and hardener (2:1 by volume for the stuff I use) very accurate, and mixing it thoroughly. I keep around the mixing container to check afterwards that everything cured and that no uncured epoxy is still sticking to the walls of it.

Is this what you were thinking?
  1. remove remaining support
  2. sand around it
  3. cut new wooden support to required length
  4. coat it in epoxy resin on all 6 sides and let cure
  5. place
  6. place strips of fiberglass to form a new collar
  7. wet each layer out with epoxy resin
  8. if necessary, wrap in plastic foil to hold together until cured
Seems workable to me (I added the bit about coating the post, because that's the only way you'll keep it from rotting).

If there's any complication that I should have noticed from the pictures, my apologies.
~ green ~ lake ~ ~
GreenLake
 
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Re: Questions on repairing a rotted mast support

Postby GreenLake » Mon Jun 29, 2020 1:18 pm

When working through an inspection port, you might like to make your own fiberglass "tape": cover your workbench with a sheet of plastic. Lay down a strip of plastic that will act like a "backing tape". Place on that the strip of fiberglass cloth and the wet it out with resin. You can now lift the tape with your backing and maneuver it in place, where you pull off the plastic. (You may even be able to prep multiple layers of cloth in one go - in that case, you can leave the plastic backing in place until the resin has cured).

The collar you are building should mainly serve to position, not to hold much load.
~ green ~ lake ~ ~
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Re: Questions on repairing a rotted mast support

Postby suthe245 » Mon Jun 29, 2020 1:52 pm

Sorry about the picture quality it is a little hard to maneuver my phone in there. You got it right though, the bottom part looks just like a 2x4 piece of wood and it extents about 3 inches up from the bottom of the boat. The piece on the top is a lot bigger, about half a foot in diameter and only about half an inch thick. There is a 2 inch gap between the 2.

Thanks for the advice I definitely have a better idea of that I should do.
suthe245
 
Posts: 2
Joined: Mon Jun 29, 2020 9:45 am

Re: Questions on repairing a rotted mast support

Postby GreenLake » Mon Jun 29, 2020 2:16 pm

Glad to hear that. Hope you can get it done.
~ green ~ lake ~ ~
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