MDO etc.
George Buehler has written about using MDO in "Buehler's Backyard Boatbuilding" and recommends it for his designs. I have used it for interior bulkheads with good results, but not (yet) on exteriors. You might want to consider an epoxy coating under the paint, but it may not be necessary.
To the person planning a painted hull with MDO bottom and plywood sides: I recommend you avoid Douglas-fir marine ply like the plague (for this application) if you want your paint job to last. I built a 6-Hour (really 6-Year) Canoe out of it and even with epoxy coating the microchecks came through and cracked the (expensive) paint within weeks. I will certainly use okoume or better marine ply the next time. The difference is that D-f ply is normally made of rotary-peeled veneers (think of a pencil sharpener) that tend to crack when flattened out, while higher-grade marine ply is (we hope) made with sliced veneers. IMHO the reduced aggravation is worth the increased expense.
Greg DeCowsky
To the person planning a painted hull with MDO bottom and plywood sides: I recommend you avoid Douglas-fir marine ply like the plague (for this application) if you want your paint job to last. I built a 6-Hour (really 6-Year) Canoe out of it and even with epoxy coating the microchecks came through and cracked the (expensive) paint within weeks. I will certainly use okoume or better marine ply the next time. The difference is that D-f ply is normally made of rotary-peeled veneers (think of a pencil sharpener) that tend to crack when flattened out, while higher-grade marine ply is (we hope) made with sliced veneers. IMHO the reduced aggravation is worth the increased expense.
Greg DeCowsky