Friday, August 26, 2016

New Design Model, Part II

With an outboard engine, all the power and 300+ pounds of weight rest on the engine support; thus, that area has to be very strong.  The engine support itself should be 2" thick; weakness can easily result if that thick, solid plywood support isn't adequately integrated to distribute its stresses to the surrounding structure.  My solution has been to recess the engine support into the stern of the boat.  In this way it is linked to the last three frames of the boat, to the keel, and hull sheathing.  With a fiberglass-wrapped, bonded hull structure, forces are dispersed into the entire hull structure.  The hull extensions behind the transom provide buoyancy for the weight of the engine, act as trim tabs, and aesthetically help blend the size of the engine into the overall boat shape.
A splash well has been included in the support design.  This allows the engine to be raised and tilted forward while allowing a rear deck and splash protection for the cockpit.  The engine support is angled at 14 degrees, the splash well bottom is angled to drain to the rear, and the well sides flare from bottom to top, providing more space for the engine itself than the lower unit.  None of this is "cut to fit"; with the hull being designed mathematically, all dimensions can be pre-cut very exactly.  The angles in this structure actually make it easier to put together; even without adhesive, the pieces are wedged together in a tight fit.

I have had time this weekend to fully sheath the model (my wife is out of town), and I am very satisfied with the result.  I'll post some photos; what do you think?

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