Hi everyone continuing with the sanding down and have come across my first problem the 'keel' at the stern has two screws approximately 2 1/2" long that are drilled into the bottom of the boat that have now failed around the holes the wood has rotted. My question is should I drill out a slightly larger hole and fill with dowel and Cascamite or does anyone have any other suggestions please.
Many thanks
I would recommend using epoxy rather than Cascamite. In my opinion Cascamite and other Urea / formaldehyde glues are completely outdated for marine use.
Interesting....I would remove all rot, and if you mix epoxy with microfibres and collidial silica (to keep it in place), then apply smooth and fair off..
As an alternative you could see if you can remove the keel (and bilge keel) altogether, not now needed for class rules and just adds weight, esp if held in with brass screws.. You will need to replace it with something, possibly a thinish piece of ply. If its rotten at the stern it probably will be elsewhere, esp if the boat is 45+ yrs old. However that depends if you want to carry out spot repairs or major surgery! Good luck..
Investigate thoroughly to see if the keel is sound farther forward - if moisture has got in under it there may be some nasty surprises or it may just be separating fron the hull - in which case you can clean up the mating surfaces and glue it back in place.
I would think twice before removing the keel. On my Mark 12 (see database entry for N2255) the centreboard edge lies just above the bottom of the keel - if you remove it you'll be exposing your centreboard and either you'll have to plane a strip off the leading edge of the board or move the board up in the case by changing the pivot posn for the centreboard bolt in order to fit a slot gasket. This in turn may mean the plate no longer fits in the case. I'm not a fan of keel removal - especially on the older planked boats where the keel timber is structural and provides longitudinal stiffening for the hull.
The screws go up and into the hog. Is that rotten too? Try drilling a larger hole to investigate by all means - a Forstner bit will give you a cleaner edge. If you use epoxy you will need to make sure that the wood is completely dry.
You will need to clamp the keel firmly to the hull while the epoxy is curing.
Good luck
Tim