The force of the wind on an anchored boat and thus the wind-induced load on ground tackle—depends on two factors: the wind speed and the exposed surface area of the boat. While wind speed is easily measured, exposed surface area is more difficult to discern. From the boat’s length, beam, and height above the waterline, we can derive a first-order estimate, but design and gear play a large role as well. A sailboat equipped with roller furling, a large pilothouse, or a bimini—or a power cruiser with a canvas-enclosed flying bridge .
We can calculate forces exerted, or load, due to wind (Fw) on a given vessel by means of the formula: