Going wider has a real negative effect on platform stiffness. So the first F16's (Taipans) had to be stiffened up or they would walk over the waves far too much. The first F16's were hard to build down to minimum weight as the hulls are just significantly larger then the older Taipan. Part of the solution to both problems was found in using two 80x2 mm round tubes as beams. They are both significantly stiffer and lighter at the same time. Also this section is easy to get in most places, it is quite common.

Wouter