One more time: I swore I'd never do it again, but I am- just got a 1979 Oday 25, and like my previous one, the transom plate/motormount area is rotted out, as is the king plank. I have seen others with this problem, and thought I'd post some photos.
This is the start of grinding, and halfway through. I've got about 10 hours into it so far, and probably have another 5 to go.
The plate is a piece of 30x30" 1/2" plywood poly'd down to the hull, then sealed with poly. The thru-hull hole edges were not sealed after install, so any water that got in the gudgeon / battery cable holes went right into the wood.
The top half of the motor plate is solid, but the bottom is not, as is the whole king plank. The latter popped right off after I cut the tabbing with a right angle grinder. Wet all the way up.
My only solution tho this is to use the grinder to grind off all the old wood and poly, with the coarsest paper I can find, like a 12-20 grit. Nobody seems to make anything low profile that will fit up in the space between the top of the cockpit and transom- it's tight. This is a full bunny suit, ear muffs, filter can respirator, and goggle/face protection job. If you can spring for a full-face mask, I would ($125) .... An air compressor to blow off the dust would be good too.
So: Score the poly on the plate with a cutting blade; pry that off with a chisel. Try to cut a bit into the ply to score the wood, and chisel that off in sheets as much as possible. You might find hollow spots under the wood where the poly putty didn't make contact with the hull, and you can just break those out too. A hammer, pry bar, and chisel are handy here.
It's very uncomfortable - I'm 5'8" 160, and have a hard time squirming around under the cockpit. There is no place that is not angled, to sit. You will be lying on the bottom at one point, grinding over your head one-handed when doing the cockpit stern area, so it's all going to fall on you. I had 4" of grinding dust in there when done the first time.
Install is pretty easy : cut 3 pieces of 1/4" ply and shape them to the hull area. Press one to the hull while somebody sets the hole locations outside with a drill. Use that piece to set the holes for the other two, then drill 1" holes through all 3 panels together, so as to be able to then fill the holes individually on each panel with thickened epoxy. Those will be drilled out later for motor mount install, etc. I put duct tape on one side of the holes, then filled them. If you line the panels up on a bench, the filling goes quickly.
Once you get the panels done, set ONE in place inside, and with the motor mount outside as a guide, use a long drilll 1/8" bit to set the new holes in one panel. Wet that panel out (I used epoxy and epoxy deck putty) deck putty it, and fit back into place inside using the bolt holes to line it all up. It's gonna be gooey. Use large 2" fender washers to hold it in place, and tighten it down to the hull with 1/8" bolts. Same for the king plank : shape, drill / fill holes with epoxy, and glue in.
Once the first panel is set (wait overnight at least) , remove the bolts (if the epoxy is holding them, use a torch to heat them JUST enought to loosen them up. I used 3" SS bolts with the threads outside just for this) . Sand smooth any bumps on the new panel. Wet out the second and third panels and bolt them down to the first. Let it all harden, sand smooth, and then poly the whole panel with 2 coats. I also deck puttied the panel perimeter to the hull, for edge strength.
I vacuumed blew out the whole boat, headliner and bilge, then washed it twice to get all the dust out.
Re-drill all the holes to the correct size, and install your stuff! This is a JOB, best done on cool days (like 40-50, for the grinding), but when you are done it will be better than the original install. The first one I did is rock solid, and my dear ex-wife is enjoying that...
I will update with more as I get to it. The weather is becoming a factor.
This is the start of grinding, and halfway through. I've got about 10 hours into it so far, and probably have another 5 to go.
The plate is a piece of 30x30" 1/2" plywood poly'd down to the hull, then sealed with poly. The thru-hull hole edges were not sealed after install, so any water that got in the gudgeon / battery cable holes went right into the wood.
The top half of the motor plate is solid, but the bottom is not, as is the whole king plank. The latter popped right off after I cut the tabbing with a right angle grinder. Wet all the way up.
My only solution tho this is to use the grinder to grind off all the old wood and poly, with the coarsest paper I can find, like a 12-20 grit. Nobody seems to make anything low profile that will fit up in the space between the top of the cockpit and transom- it's tight. This is a full bunny suit, ear muffs, filter can respirator, and goggle/face protection job. If you can spring for a full-face mask, I would ($125) .... An air compressor to blow off the dust would be good too.
So: Score the poly on the plate with a cutting blade; pry that off with a chisel. Try to cut a bit into the ply to score the wood, and chisel that off in sheets as much as possible. You might find hollow spots under the wood where the poly putty didn't make contact with the hull, and you can just break those out too. A hammer, pry bar, and chisel are handy here.
It's very uncomfortable - I'm 5'8" 160, and have a hard time squirming around under the cockpit. There is no place that is not angled, to sit. You will be lying on the bottom at one point, grinding over your head one-handed when doing the cockpit stern area, so it's all going to fall on you. I had 4" of grinding dust in there when done the first time.
Install is pretty easy : cut 3 pieces of 1/4" ply and shape them to the hull area. Press one to the hull while somebody sets the hole locations outside with a drill. Use that piece to set the holes for the other two, then drill 1" holes through all 3 panels together, so as to be able to then fill the holes individually on each panel with thickened epoxy. Those will be drilled out later for motor mount install, etc. I put duct tape on one side of the holes, then filled them. If you line the panels up on a bench, the filling goes quickly.
Once you get the panels done, set ONE in place inside, and with the motor mount outside as a guide, use a long drilll 1/8" bit to set the new holes in one panel. Wet that panel out (I used epoxy and epoxy deck putty) deck putty it, and fit back into place inside using the bolt holes to line it all up. It's gonna be gooey. Use large 2" fender washers to hold it in place, and tighten it down to the hull with 1/8" bolts. Same for the king plank : shape, drill / fill holes with epoxy, and glue in.
Once the first panel is set (wait overnight at least) , remove the bolts (if the epoxy is holding them, use a torch to heat them JUST enought to loosen them up. I used 3" SS bolts with the threads outside just for this) . Sand smooth any bumps on the new panel. Wet out the second and third panels and bolt them down to the first. Let it all harden, sand smooth, and then poly the whole panel with 2 coats. I also deck puttied the panel perimeter to the hull, for edge strength.
I vacuumed blew out the whole boat, headliner and bilge, then washed it twice to get all the dust out.
Re-drill all the holes to the correct size, and install your stuff! This is a JOB, best done on cool days (like 40-50, for the grinding), but when you are done it will be better than the original install. The first one I did is rock solid, and my dear ex-wife is enjoying that...
I will update with more as I get to it. The weather is becoming a factor.
Owww.