An old canoe can be refurbished and look almost as good as new, if the plastic is in good shape. All the wood work can be removed and replaced, leaving your canoe looking great.
Step 1: Remove old wood
Anything that is dry rotted needs to come off. Very helpful if you clearly mark the placement of seats, thwarts & etc on the inner hull to ensure that you get everything back where you want it. Also, be sure to save everything you remove, as you will need it as a template to cut your new pieces to fit.
This is also a good chance to scrub all the old dirt and grime off the hull.
Step 2: Build gunwales
If there is a good shop near you, you can buy different types of replacement gunwales. I opted to buy "knock down gunwales" online
. They are 18 foot ash gunwales that have been cut into 3 sections for cheaper shipping. They have scarf joints cut with pre-drilled screw holes to join. All you have to do is to epoxy the joints, then screw the parts together.
Step 3: Cut replacement seats and thwarts to proper length
Cut the replacement seats and thwarts to the proper length, using the old ones as templates.
Waterproof all the new wood with a sealant like Watco
Step 4: Attach the gunwales (1)
Start with the inner gunwales. I put clamps in the middle, and at both ends. Tack the inner gunwales in place with a few screws in the middle, and trim the ends.
Step 5: Attach the gunwales (2)
Now, clamp the outer gunwales in place. Starting in the center, and working your way to the ends, place screws every 6-8 inches, avoiding pre-existing holes. The screws go from inside toward the outside. The gunwales, being narrow strips of hardwood, will be predisposed to split. Try to avoid this by drilling guide holes with a #8 countersink bit and soaping the threads of the screw before inserting. The last 3 or 4 screws in the bow and stern will need to be driven from outside to inside, because there isn't enough room in side the canoe for the drill or screwdriver.
With both inner and gunwales securely attached, trim ends.