This paper presents a practical hydrodynamic optimization tool for the design of a monohull ship. The main components of this tool consists of a practical design-oriented CFD tool, a NURBS representation for the hull surface, and a gradient-based optimization procedure. The CFD tool, which is used to evaluate the steady flow about a ship, is based on a new theory, called Neumann- Michell (NM) ... [Show full abstract] theory. The wave drag predicted by the NM theory is in fairly good agreement with experimental measurements. The hull surface is represented by NURBS, which allows for the large variation of hull form during optimization cycles. For purposes of illustration, the classical Wigley hull is taken as an initial hull and the hydrodynamic optimization tool is used to determine the optimal hull forms for three design speeds and for a given speed range with displacement constraint. Copyright © 2008 by The International Society of Offshore and Polar Engineers (ISOPE).