Crack in Centerboard

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derekcjackson

Member
Last weekend after a capsize we accidently put a 3-4 inch hairline crack on the trailing edge of our centerboard. The blade is now extremely weak near this crack and can be flexed. Does anyone have experience fixing this type of damage or have suggestions on how to do it?
 
Assuming the crack goes from back toward front, it's easy. It's still pretty easy if it goes the other way, just not as easy.
Anyhow, take 100 or 150 grit sandpaper and sand the crack into a v-shaped channel on both sides. Take lighter grit paper and gently sand the surrounding area, then clean it off with thinner.
Tape the area immediately surrounding the crack over with packing tape. Mix up some West System epoxy with a 50/50 mix of high and low density filler. The consistency should be about like peanut butter. The mix of densities workds best here because it is a good balance of strength and sandability, so you won't haveve a high spot after final sanding.
Place some of the epoxy in the channel you have sanded on the crack. Tape it over with more packing tape. If you do a really good job taping you will save yourself nearly all of the sanding.
Flip the blade over and repeat the process on the other side.
Allow at least 24 hours to dry. After this time, sand the area using a sanding block and long strokes. Start with 150 grit and then quickly progress to 220, then 400 wet sand.
Your board will be in fine shape after you do this. If you wish to get it painted white, white Krylon brand spray paint is a near perfect match for the original paint. Follow directions on can.
 
i had the samething happen in the last race of the last nationals when i finished the race i pulled up my centreboard to float down to a mate and relised that it had a huge crack the same as yours so i claimed insurance and got a new one :)
 
hoipolloi said:
From my reading of the post the crack is running vertically "on the trailing edge" of the centerboard.
Click to expand...

If that's the case, and the crack is 3 to 4" long vertically but not very deep (less than 1/2"), then there is a good technique that's easy. File the eges of the crack in a "v." Take some packing tape and stick it to one side of the board along the crack. Fold the edges of the tape over the trailing edge at the ends of the crack to create a reservoir. Mix up resin/thickener as described above, and pour it onto the crack in the tape reservoir. Then fold the tape over to seal the whole thing.

Allow 24 hours to dry (but if it happens at the end of a day and you need the board to sail tomorrow, you can sand it after allowing an overnight dry), then sand down flush as previously described.

If the crack is deeper, you will need to reinforce the fix. Do exactly as above but preceed the whole operation by inserting some sort of rods into the board from back to front. Thin (1/8") wood dowels work best. Drill into the back of the blade in the cracked area, put some resin on the front end of the dowel, and put it in the blade. The dowel should end before the line of the trailing edge, by about 1/2". Use about 1 dowel per inch of crack.

You will need to tape pieces of tape together edgewise to create your reservoir when repairing a deep crack like this.

You can fix a surprisingly large crack this way. One of the things to watch out for is that you may have trouble with bubbling in the resin when you do a big fix. Large volumes of resin create a lot of heat, which sometimes causes bubbles. When doing a repair that requires more resin than will fill up a shot glass more than about 2/3s of the way, try to keep the ambient area in which you are working at about 65 degrees, and work in a dry place. This has somewhat limited the chances of bubbling in my experience.
 
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