Aircraft don't fly off the tops of waves; boats do.While the bottoms of hulls take the major brunt of stresses, and must be designed to withstand them, the monocoque construction still plays a major role in providing strength to the overall structure.It will set the necessary foundation for this continuing series of essays.
Unless the hull has an adequate system of framing and girders to span the unsupported sections, like a bridge it will buckle and collapse.
We can add to this the fact that boats are dynamic objects; they often travel at high speeds over rough water and even occasionally, if not frequently, become airborne.
To make matters worse, there are very few avenues for dissemination of information, and virtually no one who maintains any kind of database on hull failures.
This essay will attempt to illustrate the most common defects, the cause and the visible effects that the surveyor can use as a basis for conducting a thorough structural survey.
Thus, the stresses on a boat hull are far more than a matter of just gravity and mass, but are multiplied by velocity and compounded by slamming.
And as anyone who has ever done a belly-flopper off a diving board knows, water becomes hard as a rock when a wide, flat object falls upon it squarely.
Thus, decks and superstructures also constitute major structural elements of most boats and ships.
And here it is that fiberglass boats develop similarities to modern jet aircraft.
A discussion of these similarities will help us to better understand the forces that act on a boat hull, and the structural principles required to build one.
Boats are similar to bridges in that the hull must have a framing system to support it because the hull itself, like a bridge, spans a fluid substance.