Situations and Solutions
Here are some hypothetical situations for which I’ve proposed solutions along with some rationale to help you decide what to do in your particular situation, even if it’s slightly different.

1—The old girl needs refastening again. But the old fastenings won’t come out easily or at all, and there’s no more room in either the planking or in the frames for another set of fastenings. (Remember that fastenings are most effective near the edges of the planks, and that area is all used up.) The second round of fastenings is often the coup de grace for bent frames, especially those in lightly built boats. All the extra holes weaken the frames, which often break at places where the bend is more than moderately severe. The best plan of attack here is to replace the frames, plugging extra holes in the planking so the new screws can be driven in the right places in the planks.

However, if the condition of the rest of the boat doesn’t warrant the expense of replacement, if the old frames aren’t badly cracked, and if the hull still has its shape, it may be better to sister the frames and refasten into the sisters than to weaken the original frames by driving them full of more fastenings. This method can add a lot more mileage to an old hull quite inexpensively; not only is the hull shape stiffened and stabilized, but the old frames are a lot less likely to break afterwards and cause deformation. Conversely, weight is added, a lot of extra holes are put in the planking, and the boat is altered from the way it was originally built. For this method to be effective, the sister frames should extend all the way from the floor timbers to the sheer clamp.

2—The old girl needed refastening again about 10 years ago but didn’t get it. This situation is similar to the last one, except that now the planks have started pulling away from the frames, the seams have opened up and have probably been recaulked in places, and it’s likely that some of the frames are cracked badly enough to cause a loss of hull shape. There may be an accumulation of paint or debris, as well as additional caulking in the openings where the planks and frames have begun to separate.

Again, reframing is the best course of action, and since there will be more than a few isolated frames involved, last and of have course more the job will be quite extensive. Once the planks start pulling away and the seams begin to open up, it’s unlikely that sister framing will be able to pull things back together. And if the hull shape has been lost, it’s almost impossible to restore and retain it by sistering. When things have reached this stage, it’s also likely that the fastenings at the upper and lower ends of the frames, i.e., those to floor timbers and sheer, are starting to go. At this point, it’s almost a sure bet that simply refastening into the old frames will not be a success.

If an entire reframing job is out of the question, consider replacing only those frames that are actually broken or cracked so badly that a kink has developed in the hull. This will restore the shape and bring together the open seams. In other places, where the planks have pulled away from the original frames but the hull shape is intact, reef out the seams to clean out any obstructions behind the existing frames, then install sister frames. (I’ll discuss specific techniques to use in a later article.)

3—The boat has a few scattered cracked frames. In this situation, sister framing may make the most sense. As long as the cracked frames aren’t all in a line, and there’s been no serious loss of shape at the cracks, new sister frames extending well above and below the damaged area should stabilize things. If there is a little bit of a kink in the hull next to a frame crack, don’t try to bend the sister frame into the kink (remember the bend severity discussion), or it will break there a few years down the road. If a frame has cracked under the bilge stringer, the sister frame will have to be a bit smaller in its molded dimension than the original so it, too, doesn’t get damaged by contact with the stringer and eventually break.

4—External damage has broken and cracked a few frames; everything else is OK. This is a situation similar to Number 3, and again sister framing may make sense, especially if it eliminates the need to tear out a lot of the interior to gain access. The sister should extend well past the damaged area in both directions (at least four or five planks in each direction from any detectable damage) and as a rule should never end in the middle of a curve. If things are easily accessible, however, remember that replacing a few frames is not that big a job and the boat will be as originally built with no extra weight or holes in the planking.

5—There are many small fractures, and possibly a few big ones, in a lot of frames through the turn of the bilge. This problem is very common and is almost always due to a design deficiency. The frames were either bent too severely or the fastenings were driven too close to the edges, or both. If the boat is planked with mahogany, the problem may be that the frames are simply too small in cross section for that type of wood. The problem usually gets worse, eventually ending in complete fractures and loss of hull shape. The original fractures usually occur soon after the boat is built, and some may have even developed during construction. Frames against double planking may remain stable for a great many years after the initial cracking, as long as the frames’ unsevered fibers provide the necessary strength. In such cases, the frames often end up failing because of decay caused by moisture that has collected in the cracks.

If reframing is out of the question, sister framing may stabilize the boat almost indefinitely provided there aren’t any bad kinks in the hull or evidence of transverse tension loads on the planking as indicated by open seams and split planks. These sister frames may be placed in the middle of the frame bays except where butt blocks interfere. (Don’t remove a butt block, figuring that a sister frame down the middle of a frame bay will take its place.) Where there is a butt block, install the sister frame next to the original frame, cutting enough of the butt block away to let the sister frame pass by. Sister frames should run at least from the gently curving topsides to the flat area below the turn of the bilge. When the hull is single planked, frames cracked from severe bending usually deteriorate in time and completely break, and the fairness of the inside of the planking is lost. After this happens, sister framing must be considered a last-ditch stabilizing measure for a hull that really needs reframing a measure that may be the only practical solution if the boat’s overall condition is marginal.

Whether you replace broken frames or decide to sister them, you should make changes so the new frames or sisters don’t develop the same problems. If the bend is too severe, you can