I was looking at a friends clinker Folkboat at the weekend. I found cracks along the edges of a few planks, just aft of the chainplates, in the vicinity of the waterline. The cracks are right along the rivet line of the lands (where one plank overlaps the other) extending over a distance of about 1 metre. This features across a few parallel planks. The cracks are very clearly visible on the inside and can also be seen under the exterior paint, so are developing right through the lands.
I suspect this has been caused by the short aft chainplates that have been fitted and the resulting stress across the planking when the boat is heeled. Some of the frames are doubled in this area so my suggested solution is to scarf in new sections of planks and to put in much a longer aft chainplate, extending 2 or 3 planks lower than the cracked planks.
Has anyone come across this problem on clinker Folkboats before and is there a best practice solution?
What would you do?