A rational way of considering a ship resistance problem as a small perturbation based on the equation of motion of a viscous fluid is shown. A ship surface condition, which has made it hard to linearize the problem, is considered and it is shown that a volume distribution of singularities is necessary to satisfy the condition. The singularity distribution is related to the boundary layer's quantities, such as displacement thickness and momentum thickness. Next, resistance formulas of O (|υ|) and O (|υ|²) are derived from momentum analysis respectively, where υ is perturbation velocity. A resistance of O (|υ|²) includes a component of “wave wake” formed by the damping of wave motion on account of the fluid viscosity.