However, selection of the right wood is only one part of the equation. In this case, mahogany was used. Unfortunately, this was a double planked bottom and only the outer layer was replaced; the original inner layer was left cedar.
This mismatch of wood might have been ok if the two layers had been appropriately fastened, and if an appropriate caulking and membrane material had been used.
This particular repairman had used a black rubber material similar to roofing tar as both a membrane and a caulk. This material cured very hard. The combination of a hard caulking material with a hard wood like mahogany did not provide for the eventual expansion of the wood when wet. A more appropriate caulk would have been either cotton wadding of a polysulfide like Lifecaulk.
The unfortunate result was a bottom that expanded when wet, then popped. Since the wood couldn't expand between seams, it expanded away from the inner layer. Originally clinch nails were used to fasten the outer layer to the inner. This repairman used only screws through the two layers into the ribs. I think the black rubber was to act as an additional bonding material. However, this bond was not sufficient. The mahogany buckled out away from the bottom, creating large holes.
The sad end to this story is that after we did our work to the topsides and rig, the boat was ruined by vandals. The hull was damaged beyond repair.
For those of you interested in the final resting place for this boat—I've cut it in half. One half is being donated to a museum for a display. The other half will become a desk in my home.
CONTACT the ILCA Office
for more information.