Hi I will try to point you in the best direction.

First if you need to take out the centre board and I presume you mean the cb case, this is a very major job not to be undertaken without some detailed preparation.  Details on how to do this can be found in the library under the members tab on this web site.  If all you need to do is removal of the cb itself simply undo the bolt and slide the board out.

Second question on how far to chase out the rot, I would normally recommend that you carefully identify the location of the frames either side of the rotten areas cut out along the centreline of the frame, missing any screws, cut a new piece of ply to fit the area cut out and fit with epoxy glue and filler.  The area you are repairing may need you to remove all or part of the keel to ensure the new  ply to the hog.

i would also suggest that you buy a set of the plans for the construction of a series 1 wooden GP14 from the office, this will help you to understand how the boat is constructed

Hope all goes well Steve Corbet

I’ll try to answer your questions in order

1 if you work out where the frames are which surround your rot you then need to cut the old ply  along  the centre line of the frames, this helps you to replace the new ply with the same curves as the original ply.  Because you are using the frames to support the new ply edging or backing pieces are not needed.   As for which epoxy to use either SP 106 or a WEST product will be easy go use make sure you buy a pack which includes measuring pumps or syringes, always measure the quantities carefully and at the recommended temperatures.

2. If you need go cut out part of the keel a scarf joint will allow the strength to be maintained over the rebuilt joint

3. The screw holes should not be a problem as the screws are a tight fit in the wood, all old holes should be filled with an epoxy filler marine grade Plastic Padding is easy to use.

if the paint is flaking it is a sign that a previous owner has not prepared the hull by rubbing down the paint before painting.  Given the amount of work you will be doing in replacing the  rot I would recommend a completed stripping of all the paint, refill all screw holes as the old filler will pop out as you remove the paint, then repaint with good quality paint prime, two coats undercoat and one or two topcoats.

Steve

I am picking up this thread somewhat late,   not least because I have been off the forum altogether for perhaps a couple of months while initially away sailing and then caravanning,  and on top of that I have also had a major upgrade to the computer  –  and by my oversight this forum was one tab that I failed to reload when I got the machine back.

<span style=”line-height: 1.5em;”>Steve has already answered most of your queries,  but I pick up one point in which you specifically referred to myself;  cutting the keel,  and scarf jointing it.    Although the hog (the very substantial timber inside the boat,  along the centre line) is very definitely structural,  indeed it is the backbone of the boat,  the keel (the corresponding piece on the outside) is of very much lighter section.   Since the whole boat is massively strong,  some might even claim her to be over-engineered,  you can afford not to  worry too much about preserving the strength in the keel itself,  provided the hog is sound.</span>

So,  yes,  if the hog is in good condition you can regard the keel as little more than a non-structural exterior capping piece.   So if you want the easy route,   take off the keel band first,  then a straight cut is a sufficient means of cutting at either end of the section that you need to remove.   Extract the screws (you may well need to strip the paint off the keel in order to locate them),  and if you are VERY lucky you may then find that the glue is on the point of failure anyway and you can simply insert a sharp chisel underneath it (as flat as possible to the plywood) and force it off in one piece.   Then when you later re-assemble,  you can indeed just refit this piece.

However it is much more likely that the glue won’t fail,  and you will have to cut away the wood from the top,  paring it down with the chisel (or other method/s of your choice).   In that case,  when you come to reassemble you won’t have the piece you removed,  just a pile of shavings,  and you will need to let in the appropriate length of new wood.   In that situation you might as well go all the way,  cut the new timber longer than the gap,  and do scarf <span style=”line-height: 1.5em;”>(a.k.a. scarph)</span><span style=”line-height: 1.5em;”> </span><span style=”line-height: 1.5em;”>joints at either end;  it will be neater,  and even though strength here is not a major issue you might as well have the extra strength.    </span>

A plain scarf joint is perfectly adequate if you use a good epoxy glue,  but I would also use screws to hold it while the glue sets,  and I would leave the screws in when the job is finished:     http://en.wikipedia.org/wiki/Scarf_joint

Ideally,  if you do that,  use a gradient of about 1 in 12,  i.e.  for every one inch thickness of the keel use twelve inches length for the taper (at each end).     I think you will in fact find that the keel is only about half an inch thick,  in which case the length of the taper should be about six inches at each end,  but I haven’t measured.    If you are absolutely confident that you are getting your mating surfaces perfectly true then you can use neat (unthickened) epoxy,   but if you have any significant gap to fill then thicken the epoxy with the appropriate microgranules.

Oliver