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With limited room, removing the old concrete required some contortions and lots of creativity. Frank used a sledge hammer and chisel to excavate ballast. Once he reached more intact concrete, he was able to clean things up quite effectively using an Makita Angle Drill tipped with masonry bits and DeWalt 4 ½ Heavy Duty Grinder fitted with a Hitachi Premium Diamond Turbo Blade. Finally, a Dremel tipped with a grinder head reached the tighter spots until all that was left was clean, dry concrete. Fortunatey the saturation extended only a few inches up.
Our goal was to rebuild the area and restore it to maximum structural strength, and that involved reinforcing the core as well as grinding away ¼" of exterior fiberglass so that we could then wrap layers of cloth and mat in alternating directions until we reached proper dimensions.
(CRITICAL NOTE: Make marks along the keel beyond the area of work. These marks provided reference as we proceeded and allowing us to rebuild this area to the precise dimensions needed and align the skeg.)
Frank's approach to fiberglass removal. Using the Diamond Turbo Blade on the grinder and a VERY steady hand, he scored the fiberglass. The shop vac limited fiberglass dust somewhat. Once scored, Frank removed the outer layers with a wood chisel.
Next: we sanded down with a DeWalt 80 Grit Zirconia Flap Disc creating a gradual taper around the perimeter to a 12:1 bevel angle. this left a smooth but adequately roughed-up surface, giving the first layer of resin and fiberglass cloth sufficient "tooth" to grab.
We measured the void and constructed a replacement core by sandwiching biaxial/mat fiberglass (15 oz. non-woven E glass fabric 2 layers, 45 fiber orientation with a .75 oz./sq. ft. mat backing) between three layers of ½" thick teak, laminating it with West System epoxy and clamping it overnight. The West metering pumps took all the guesswork out of mixing correct ratios.
The void inside the keel was wetted out with an ample amount of the epoxy thickened to a peanut butter consistency using West System 403 Microfibers Adhesive Filler. We inserted the new teak laminate core into the keel, supporting it from underneath with a small automotive jack to be certain it remained securely in place as it set. Once cured, we sanded off all the excess epoxy at the bottom.
Using the reference marks we made before beginning Phase 2 of our repair, we determined the center points for the skeg bolts and drilled ¾" diameter holes. The core laminate was so solid that the drill bit began smoking. We filled those holes with the reinforced epoxy until everything was solid. Once finished, the bolt holes would be center-drilled to accommodate the 3/8" bolts while leaving the teak completely encapsulated.
Before proceeding we cut the glass cloth with a sharp razor or scissors depending on the shape and the direction of the cloth fibers, preparing each piece ahead of time, storing them between the layers of cardboard, keeping them neat, clean and ready for when needed.
I took some scrap wood, clamped it upside down to create a "test keel" and experimented with bits of glass cloth. The trick, I learned, was to wet the area then wait until it just started to "kick", turning slightly tacky and far less fluid. At that point I'd apply the cloth, wet it out, roll it, squeegee the excess away, wait for that to kick, and move on to the next layer of cloth.
We built up the cut-away bottom layer by layer, repeatedly wrapping the bi-axial fabric/mat up from beneath and then from behind, reinforcing the bottom of the keel from multiple directions.
We measured to confirm that everything was within the correct dimensions. The skeg itself was extremely heavy and clumsy even for two people to handle. Frank built a precisely measured wood duplicate of the skeg mount.
This allowed us to easily check and re-check as I faired out the repaired section so that the skeg would fit perfectly.
The skeg, cleaned and primed, eased it into place. Due to the weight and limited space, the "easing" was aided by a rolling automotive jack which supported the skeg and did the heavy lifting. We reinstalled the shaft and rudder, which required the Travelift raise the boat high enough that we could c-a-r-e-f-u-l-l-y lift the rudder shaft back in place.
(NOTE: We were midway through gently jacking the rudder in position when the yard manager, ever in a rush, insisted he'd speed the process up by LOWERING the boat over the shaft. Even as we shouted "NO!" he proceeded anyways, and for a moment something hung up, with all the boat's weight bearing down. After what seemed an eternity he finally heard our frantic shouts of "UP! UP!" and lifted the boat enough for things to slide into place. Needless to say, that moment left me with a few new gray hairs, and a hope that no damage occurred.)
Everything seemed to aligned perfectly, and we hoped for the best. New holes were drilled for the skeg bolts. We re-packed the rudder and shaft stuffing boxes, then removed the skeg to prime and paint the re-glassed sections.
Additional Note on Lessons Learned, 9/27/09: Take the keys away from the travelift operator lest they decide to 'help'. That little time-saver, ultimately, only helped damage the rudder shaft and housing, costing us much of the summer and creating a new project for next winter.