Finally starting to get ahead of the deadlines a bit. Here is the hull laminate drawing by a very famous designer. I consider it completely wrong and I will explain. Every kind of forensic foray like this has teachable moments for all.
First, we surely all agree now that long, slender hulls are most loaded in bending or deflection, depending on the span. Global loads, like a wave at each end, govern over out of plane loads like, water pressure. I first learned about and began to design for global loads after the MACM ’86. This drawing below is a decade later.
We also surely agree that to resist those loads, we must have the most and best laminate fibers oriented along the lines of stress. Zero degree, along the length of the hull for these boats. That is the best way to get a stiff hull.
This drawing has the vast majority of the glass laminate at +-45. That is completely wrong to achieve a stiff hull. It does have carbon on the inside of the hull, which does protect the fragile carbon from crashes. Typically I would complain about rule of mixtures, but the carbon is also +-45 degree orientation here. The best feature of carbon, its very high modulus, is of no use in this arrangement.
And see how this is just as important for the hull deck. For water pressure, the +-45 is fine, but again, the global loads are much greater.
One of the tests I used to do before I knew what to expect was to have my guys jack up one bow of a cat, and see that the other one does. I remember hearing about Larry doing that on Sierra Cloud. The other bow not only came up the same, but took all the blocking with it.
This famous cat deflected 3-1/2″ in the same test. There is no reason to do laminates wrong. Its not a mystery anymore.
