repairing oak frames

[roophap]

hi there
a few of the oak frames on my old girl are badly damaged and i was wondering what the best method of repairing them are i have been told to cut out the bad piece and replace it with new oak others say i should replace the whole frame and someone has told me to leave the old alone and put a sister frame alongside the damaged frame any body know what the easiest strongest repair is ?

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[Peterduck]

It will depend very much on access to the frame. The very best repair is to replace the whole frame, top to bottom. However, in decked boats it is often impossible to get at the top end [head] and the bottom end [heel] of the frame where it is attached to the beamshelf and the keel respectively. A second-best method then is to make up a collection of laminates of timber, the width of the frame and about 1/8" thick. Make certain that the grain runs along the full length of each laminate, and not out to one side. These should be in increasing lengths from a little under to a little over a foot long, and arranged like a leaf spring on a car, getting progressivley longer as you get to the top. Trim back the old broken rib above and below the fracture in steps to match the laminates which you have just made. If the rest of the boat is fastened with copper rivets, remove the rivets from the trimmed-back part of the rib. Smear your chosen glue over the laminates except for the face which faces the planking. Using the old rivet holes, drill for new rivets through the new laminates and rivet up. Trim off and clean up when the glue has cured. Sister ribs are to be avoided as they simply relocate the problem to the ends of the sisters, and the old rib then breaks there too. Then you have a rib with three breaks instead of one.
Peter

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[ROAM1962]

I have been restoring a classic 1948 sloop where several timbers were broken. The surveyor said that it was OK to double the timbers up so long as I made sure that the span was three planks either side of the break. I did these in green oak steaming them in a PVC drainpipe. It seems to have done the job - but she is not in the water yet. maybe I should laminate up too, but steaming oak, although at first appearing daunting, is probably quicker than all the precision cutting required for laminating.

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[Peterduck]

Steaming and boiling [the latter being a little more effective] timber isn't difficult if you can set up for it, but that is not always the case. I must say that an enormous amount of heat has to be generated and the water boiling really vigourously, not just simmering. However, once you have those conditions, steam bending is surprisingly easy.
Peter.

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