Beam Rot - Advice & Suggestions

[Ian Bamsey]

I've discovered a section of rot in my Tiki 21 front beam.

It's a long section of rot around 20mm wide and 15mm deep running along the top edge of the lower flange as shown below.

I'm trying to think of the best approach to repair.

a) Rout right through from the bottom and epoxy in new section of wood.

b) Rout away a step from the side and set in new wood,

c) Remove the entire right hand side of the bottom flange and replace.

Suggestions would be most welcome.

Thanks, Ian

[Ian Bamsey]

I bought a nice bit of Douglas Fir today and that made the decision for me. I've cut away about 25mm from the lower flange on the beam. New wood will go in with a scarf joint in the middle and perhaps some pegs along the length. All with lashings of epoxy.

[paul anderson]

Should do the trick nicely.

[Roger]

Looking like a nice job Ian.

Ian Bamsey said:

I bought a nice bit of Douglas Fir today and that made the decision for me. I've cut away about 25mm from the lower flange on the beam. New wood will go in with a scarf joint in the middle and perhaps some pegs along the length. All with lashings of epoxy.

[sailorjoy]

Hi Ian,

I had the same problem last year. First I repair the rooten Parts of the beams but it was not strange enough. The beam broke

in rough conditions. I repair it again but it broke again. So I build new ones made of foam, carbon and epoxy.

I think its better to build new beams instead of repairing the rotten one.

Best regards

Jan

[Greg Russell]

 I wouldn't trust beams made out of foam sandwich. I made  I beams for my Pahi 31 as  one of my box beam had a hole in it from one hull to the other about 2" wide. Have not had any problems since and went from 14' to 17.5' wideand seems to sail better. I seems like a foam sandwich would have more flex in it. I try not to drill any holes in my beams. 

Hope your new beams last longer, my beams are still good 6 years on.

[sailorjoy]

Hi Greg,

I´ve no experience with carbonbeams but I hope that they hold longer than wooden beams. The foam is only for the form.

I take unidierectional carbonlayers and kevlar-carbon rovings. It feels that they are very strong.

Best regards

Jan

Greg Russell said:

 I wouldn't trust beams made out of foam sandwich. I made  I beams for my Pahi 31 as  one of my box beam had a hole in it from one hull to the other about 2" wide. Have not had any problems since and went from 14' to 17.5' wideand seems to sail better. I seems like a foam sandwich would have more flex in it. I try not to drill any holes in my beams. 

Hope your new beams last longer, my beams are still good 6 years on.

[Ian Bamsey]

Getting there

[sailorjoy]

That looks good. I hope it will be your last repair on this beam.

[Ian Bamsey]

Yes, this is a very good point and I think you're right. As you can see in the initial photo, the rot was in a line directly where the platform lies. It was evident from cracks in the paint along this line.

There might be another factor here. These beams were built in 1984! I stripped them back and repainted with epoxy 2 pack paints 2 years ago. I wonder if some rot was already where the platform sits, then it was trapped in by the new paint. Eventually cracks formed allowing more water in. The rot was not extensive, but it was easier to cut out a full section of wood for the repair, rather than letting in a small strip.

The other areas where problems have occurred is where the lashing press on the upper flanges.

[Robert Sheridan]

We put rubber between the beam and the platform and I am hoping that that has reduce the risk of rot.

[Ian Bamsey]

The beams were originally epoxy coated. I did not apply any more when I first restoring them, I'm sure I trapped in some water and some bad wood. I stripped them back to the epoxy using peel away paint remover, then repaired some wood and repainted with 2-pack epoxy paints (Jotun Penguard HP then Flextop - I think these are great paints)

It's worth remembering these beams are 35 years old. So whatever problems I've had, they have been very good. In the recent work to replace sections with new wood, I have applied a generous coat of epoxy and today I put on the first coat of epoxy paint.

I think it is worth the effort of applying one or two epoxy coats before painting. If I were making new beams, I would first apply wood penetrating epoxy. In particular I think extra care is needed at the beam (grain) ends.

Good luck with your work. Today, for the first time, I felt like I was close to getting back in the water! 

[Ian Bamsey]

The beams were originally epoxy coated. I did not apply any more when I first restoring them, I'm sure I trapped in some water and some bad wood. I stripped them back to the epoxy using peel away paint remover, then repaired some wood and repainted with 2-pack epoxy paints (Jotun Penguard HP then Flextop - I think these are great paints)

It's worth remembering these beams are 35 years old. So whatever problems I've had, they have been very good. In the recent work to replace sections with new wood, I have applied a generous coat of epoxy and today I put on the first coat of epoxy paint.

I think it is worth the effort of applying one or two epoxy coats before painting. If I were making new beams, I would first apply wood penetrating epoxy. In particular I think extra care is needed at the beam (grain) ends.

Good luck with your work. Today, for the first time, I felt like I was close to getting back in the water!