David -
you're right, there is a lot of stuff on the index, but doing a topic search on this forum in the same way you would search for anything on the internet can give you results you are looking for - eventually
Let me save you some trouble by paraphrasing my own post on this subject from a few years back:
Beefing up, repairing and rebuilding keels is easy enough that we used to do it right on the beach. This is not pretty, but down and dirty and effective. It takes a couple hours.
Tools needed:
Sur-form file set
Several grades of Sandpaper
masking tape
newspaper
roll of waxed paper
rubber gloves
throw-away plastic spreaders
a few cheap throw away, fiber, paint brushes NOT FOAM
Bondo (clear fiberglass) or other fiberglass repair kit with fiberglass cloth
Extra f-glass cloth
VERY sharp scissors - to cut cloth with as little shredding as possible
solvent to clean up the project (de-natured alchohol)
Beer to get in mood for project (good-natured alcohol)
A friend to help.
Flip boat upside down. (It helps to remove the mast first of course
)
Mask off a line on each side of each hull about 3-4 inches below the bottom edge of keels (which are now pointing at the sky) Cover exposed upper hull with newspaper. Tape securely to keep dripping fiberglass off hull
Cut glass cloth into strips about 2 - 3 inches wide for length of each hull, make sure they overlap an inch or so on each other. cut wider if needed -place strips in a handy pile so that you can place them quickly along hull from STERN to BOW (so that overlap is toward the stern - this is not critical as the repair will lay pretty flat when done)
Put on rubber gloves, mix up fiberglass-epoxy according to directions. A half pint is enough at this time. Using a LITTLE less hardener will give you more working time. Using paint brush, spread thin layer from stern to bow. As you spread the epoxy, have friend lay down the glass cloth and press firmly into place with the spreader. Do not press too hard, just enough so the cloth is adhered to the hull and their are no bubbles. Allow to dry. If you have to wait over night for the final layers, be sure to sand lightly between coats.
If the keels are really thin, repeat above procedure with another layer of cloth. or two.
Apply a few more coats of epoxy over the cloth, as needed so that all the cloth becomes invisible. If you have voids or bubbles, dig them out and drop some epoxy directly into the hole, like a filling in your teeth.
Using the sur-form file and sandpaper blend the edge of the repair to the sides of the hull.
If you have never worked with epoxy and cloth, it comes quickly, but can be tricky. Try fiberglassing something less important first- like the bottom of your kids skateboard
It changes the "pop" a little, but is gives a good surface for board-slides. At least that's what you can tell him/her. 
Good luck.
Stephen