Steam-powered Canoes

[fredrosse]

Attaching the Outboard Lower Unit to the Scanoe hull presents some difficulties, as the Scanoe hull is HDPE plastic, and there are no adhesives that will stick to the plastic hull material.

The assembly consists of a metal backing plate inside the hull, with bolting from the metal plate to the outboard lower unit. Since the hull shape is irregular, I used ordinary "Bondo" automotive body putty to make this transition. The Bondo is mixed and hardens in about 10 minutes. An ordinary spatula was used to force the bondo between the hull exterior and the outboard "anti-cavitation" plate. The Bondo firmly attaches to the outboard lower unit metal, but does not adhere to the Scanoe Hull.

After the Bondo had hardened, the mating surfaces between the Bondo and the hull exterior were caulked with ordinary silicone bathtub caulking. The same caulking was placed inside the hull, between the metal plate and the hull interior. Then the bolts were drawn up tight, forming a waterproof "sandwich" construction as shown. A good waterproof paint was then used to seal the exterior Bondo surface.

The process with the Bondo and caulking only required about 1/2 hours work, after the bolt holes in the outboard lower unit anti-cavitation plate and the interior metal backing plate.