We were working through some design issues last week using a new (beta) version of Rhino 3D, and thought that a quick set of graphics on the FPB 64 structural grid might be of interest. These may help put the construction photos we show into context.
The structure in the bow is built with collision in mind (the model is 1.85m/six feet tall).
The stem bar is not only massively strong on its own, but it is reinforced by three horizontal web frames.
The stem bar is 40mm thick, further reinforced by the topside plate, 12mm here, for a total thickness of 64mm (2 5/8″).
The bottom of the hull is stiffened by a series of deep longitudinal girders and transverse frames. These work as baffles for the fuel and water tanks, minimizing noise from sloshing and the dangerous impact of free liquid effect in heavy going.
One of the many advantages of aluminum construction is the ability to have integral tanks. The fuel tanks, centralized for minimum impact on trim as fuel levels change, are over a meter (three feet) deep.
Fresh water tanks are on either side of the fuel tanks, separated by coffer dams (empty sections).
Integral tanks form what is in effect a double bottom, reducing the risk from a hull puncture, unlikely though that is given these scantlings.