Crack repair on the bottom board

by Wayne Doerpholz
(South Hadley, MA, USA)

I am very new to wooden boat repair.

I purchased a 10' Chaisson Semi Dory refinishing project and have it in my basement workshop.

All of the paint or varnish has been stripped from the hull down to raw wood.

The hull developed a 1/4" wide thru crack on the bottom board near the keel from the transom forward about 30" long tapering to zero.

How would a crack like this be repaired?

I am not certain what wood was used in the planking but I am assuming it was red cedar and that white pine was used for the bottom board.

The hull is very dry and I assumed this crack was caused from the wood drying as it has been stored inside for years but I am unsure if this was the cause of the crack.

If I were to added what is essentially a long wooden shim would this cause other problems when the wood swells from moisture?

My second question is should every copper rivet be worked into the cedar planking and then coated over each rivet with wood filler?

And my last question (most likely getting way ahead of myself) is how is this West Epoxy System used?

I am confident that I am capable of applying it but what will it do to the hull and can I paint over the epoxy?

I purchased this small wooden sailboat for my three grandsons to use on a shallow freshwater pond near our home.

I am trying to hold down its weight as much as possible.

I mentioned my skill level with wooden boat repair is zero however I am a 20 year maker of American Period Furniture and have a complete woodworking shop that is unfortunately too small.

I live in western Massachusetts and the Chaisson dory will only be used in freshwater.

Comments for Crack repair on the bottom board

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Apr 10, 2024
Crack Repair
by: Al

Congratulations on your new boat project! It sounds like a great undertaking and a fantastic gift for your grandsons. Here's what you can typically do to address your described issues, of course, bearing in mind that woodworking have different approaches and this doesn't replace the advice of a professional.

1. To repair the crack on the bottom board, make sure it is fully clean and dry first. You can indeed use a wooden shim or better yet, a Dutchman patch (a custom shaped piece for the gap). You could use epoxy adhesive for a strong bond. Make sure to seal the whole area properly to prevent water ingress. The swelling from moisture should not be a problem if the repair is done properly.

2. Regarding the copper rivets, normally, you don't need to coat them with wood filler unless there's a void left behind. If everything is in good condition and firmly riveted, leaving them as is should be fine.

3. WEST SYSTEM® Epoxy is a versatile product that you can use for various applications such as coating, bonding, and fairing the hull. When applying, make sure the wood is well dry and free from any contamination. The epoxy will protect and seal the wood from water intrusion. It will also reinforce the structure of your boat. Moreover, yes you can paint over the epoxy. Just make sure to follow the manufacturer’s specific instructions and recommended products for compatibility.

As a tip, considering the thickness and color of the epoxy coating is important as dark colored boats, in particular, can absorb heat and cause the underlying epoxy to soften if it’s applied too thin.

Lastly, it's important to remember that while repairing the boat, its structural integrity must be kept in mind at all times. It's generally recommended to consult with a professional boat builder for advice on major repairs.

Enjoy this project and wish you success on making your grandsons' sailing experience memorable.

Mar 25, 2023
Crack Repair
by: Mike

A shim would be the perfect solution, you could rout out the crack to make it easier to get a tight fit.
Use a wood as similar to the original as possible.

You could countersink the rivets but it isn’t strictly necessary.

As for the epoxy, it needs to be painted or varnished with a coating containing a UV protection.

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