What Is Hydrostatic Equilibrium?

The curve of the distribution of the shear force of the hull girder in still water along the length of the ship is called the still water shear curve. It is the first integration of the hydrostatic shear curve and the second integration of the hydrostatic load curve.

Hull girder ^[1]

Load curve ^[2]

Through theoretical analysis and specific calculation and comparison of 4,990-ton oil tankers, the following conclusions are obtained:

The static water shear forces, static bending moment distribution values and maximum values vary greatly between different ships and different working conditions. The maximum static water shear forces and bending moment positions are also slightly different under different working conditions, which need to be calculated carefully;

Since the hydrostatic load, hydrostatic shear, and hydrostatic bending moment are integral relationships, the zero load point corresponds to the extreme value of the shear force; and the shear force and bending moment at the end points of and should be zero;

In general, the load is approximately the same in the front, middle and rear of the ship, so the shear curve is roughly anti-symmetric, the maximum point of the bending moment is close to somewhere in the ship, and the Shear force at 1/4 of the captain has the largest positive or negative value. ^[1]