Longitudinal cracks in ribs: Glue and clamp, or lamination necessary?

by Dom Elias
(Dalsbruk, Finland EU)

We're restoring my South Coast One Design (SCOD) yacht (mahoganny on oak, 1956) and I had an idea for an alternative rib repair:

I know that usually cracked ribs are repaired by laminating/sistering/steaming of replacement ribs.

When the crack is across the rib, I see no other alternative.

Yet, for a crack along the grain of the wood, could gluing and clamping be an alternative option?

As you can see from the picture, there is plenty of material on both sides of the crack, the wood is solid on both sides.

My plan of action would be to remove the rivets first (planks in question are going to be replaced anyway) plug the holes with wooden bungs, epoxy and clamp, then redrill for the floor brackets when (re)fastening planks.

Maybe it should be said too, that the rib in question is one of 12 ribs holding the 6 metal floor brackets

So my question here is: Is gluing longitudinal splits in ribs an option you have heard of? Done it? Have a good argument for/against doing it like that?

Comments for Longitudinal cracks in ribs: Glue and clamp, or lamination necessary?

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Apr 10, 2024
Rib Cracks
by: Al

It's not uncommon to repair longitudinal splits in ribs by gluing and clamping, particularly if the wood is otherwise in good condition. Here's a breakdown of the process and some considerations:

1. Cleaning: First, clean the crack thoroughly to ensure there's no dirt or debris that could affect the adhesion of the glue.

2. Glue: For a strong bond, consider using a high-quality marine grade epoxy. It's waterproof and has excellent bonding properties for wood.

3. Clamping: After applying the glue, clamp the rib along the split until the glue has fully dried. You might need several clamps to apply even pressure along the length of the split.

Then you can proceed with the rest of your plan – plugging holes with wooden bungs, re-drilling for the floor brackets, and so forth.

However, there are few caveats:

Structural Integrity: While gluing can effectively mend a split rib, it's important the repair maintains structural integrity. If the rib is under significant stress, sistering or replacing might be necessary.

Extent of Splits: If there are too many splits or if the splits are long, again a replacement or sistering might be the safer option.

Condition of Wood: The effectiveness of a glued repair can depend on the condition of the wood. If there's rot or other damage, a glued repair likely won't hold or might be masked by the damaged wood.

Even with that said, the fact that this particular rib is one of several holding the metal floor brackets might mitigate some of these points, provided the other ribs are in good condition.

Remember that this advice is based on general experience and it can still be beneficial to get professional advice on this matter. Each boat can be unique and it's important your SCOD remains seaworthy.

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