Balsa core repair

[duefocena]

I'm looking for information on balsa core water intrusion repair. In particular catamarans that have had this issue or are known for it.

[colemj]

Cut it out, replace it, glass back in, apply finish. It is done all the time on all types of boats.

Search the net for instructions and examples - it isn't a difficult job, but it isn't a beginner one either.

Mark

[duefocena]

Thanks for your reply,
The thought of tearing out the deck of 40' catamaran sounds so critical. I was hoping to fill it in with got rot or similar by drilling and injecting

[mf70]

I did a drill-and-inject repair on my Bristol 26 for an isolated soft spot. It seemed to work well. I drilled 1/8" holes on 1" centers, injected alcohol, let it sit ~6mos., and injected epoxy in each hole.

I am sure water remained, but the epoxy "posts" at each injection spot stiffened things up nicely.

On other areas, I cut out outer f/g, scraped away oatmeal-like rotted balsa, and rebuilt core with pt plywood & new outer laminate.

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[colemj]

Originally Posted by duefocena

Thanks for your reply,
The thought of tearing out the deck of 40' catamaran sounds so critical. I was hoping to fill it in with got rot or similar by drilling and injecting

Everyone wants to do it this way, and many try and fail (or live with the failure and call it "fixed"), but the ONLY way to fix this is to cut it out and replace.

Git Rot and the like is not a fix, nor is drilling "pillars" of epoxy - it may feel firm, but it has no strength. The deck of a catamaran has large shear forces at work on it and the core needs to be correctly bonded to the skins or you will have structural problems.

It sounds daunting if you have never done it before, but it is really quite straightforward. Again, not an easy job for a beginner, but one that can be done. It is a relatively easy job for someone who does have glassing experience.

Depending on where the bad core is located and how extensive the problem is, it can be done from the inside, which will save you a lot of finish work on the outside.

Mark

[Boatyarddog]

Git rot is a no no.
Suck it up and fix it right.
Otherwise you'll never be sure.
Epoxy won't cure properly in this application.
Think about it the woods wet already.
The epoxy isn't going to penetrate the fibers, it's got no where to go.



Sent from my iPad SV Cloud Duster

[downunder]

Originally Posted by duefocena

I'm looking for information on balsa core water intrusion repair. In particular catamarans that have had this issue or are known for it.

Most of the Schonnings and Oram catamarans in Australia are built use balsa core and I have never heard of a balsa problem.

I believe Leopards and not sure of Lagoons use balsa above the water and haven't heard of any issues.

If you google search you will find many USA built monohulls and powerboats with deck issues often from holes drilled in the deck with coring the drill hole with resin.

[44'cruisingcat]

Agree, you have to fix it right. You need to open up the laminate and get to the core, clean out all the wet balsa, replace it, and glass back over it.


The actual repair is likely to be quite easy, it's the cosmetic repair that could be difficult. Usually best if you can access it from inside the boat.


And you need to find out how the water got in, and stop it!