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For a given set of ship design and operational criteria, there exists a trade-off between the ship's calm water powering performance and its seakeeping performance. Ship hulls that are designed for optimal powering performance can have poor seakeeping performance, and vice versa. It is typically not possible to obtain the global optimum for both of these objectives because of the competition between the powering and seakeeping performance functions and the design constraints. The set of globally nondominated solutions, or Pareto front, considering these competing criteria is searched for by navigating the multimodal search space using a multicriterion, population-based evolutionary algorithm optimization process. The optimization process uses a nontraditional objective function formulation that eliminates the need to tune the penalty function parameters for each new problem formulation and appears to provide a more thorough representation of the numerically approximated Pareto front. Results show that properly integrating this optimization process with the design criteria yields a set of hydrodynamically superior design solutions. The problem formulation and development is applicable to naval surface vessels and applied to a monohull frigate type example.

A large-scale surface effect ship (SES) bow seal testing platform was constructed by the University of Michigan and is presently being commissioned at the U.S. Navy's Large Cavitation Channel (LCC) in Memphis, TN. Using a recently installed (2008) free-surface forming gate, the test platform is capable of investigating the physics of the two-dimensional planing seal and three-dimensional finger-type bow seal in calm water conditions and at scales relevant to SES designers and numerical modelers. The LCC environment permits extended run times at high Reynolds number and provides unfettered optical access to the seal geometry and flow field. This article describes the development of the testing platform and presents some preliminary results. The test platform is nominally 7.9 m long, 1.52 m wide, and 2.0 m tall and of welded and bolted steel construction. The seals are nominally sized similar to those currently used by the U.S. Navy's Landing Craft Air Cushion class. An extensive measurement suite was integrated with the test platform. The goal was to provide numerical modelers a data set with sufficient spatial and temporal resolution to validate their models of the experiment and, where appropriate, to develop new analytic models. The results of this effort demonstrate a feasible system for investigating surface effect ship seal physics within a large free surface water channel.

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