This paper proposes a total-ship system design and requirements definition methodology that includes important components necessary for a systematic approach to naval ship concept design. The methodology is described in the context of an Offshore Patrol Vessel (OPV) project conducted by senior undergraduate design students at Virginia Tech. Concept Exploration trade-off studies and design space exploration are accomplished using a MultiObjective Genetic Optimization (MOGO) after significant technology research and definition. Objective attributes for this optimization are cost, risk (technology, cost, schedule and performance) and mission effectiveness. The product of this optimization is a series of cost-risk-effectiveness frontiers which are used to select alternative designs and define Operational Requirements based on the customer’s preference for cost, risk and effectiveness.
The notional OPV requirement is based on an OPV Initial Capabilities Document and Virginia Tech OPV Acquisition Decision Memorandum (ADM). The OPV is intended to replace the in-service US Coast Guard (USCG) Medium Endurance Cutters (MECs) including 13 Famous Class cutters (82.3 meters, built in 1980s), 16 Reliance Class cutters (64 meters, built in 1960s) and 2 single cutters built in 1944 and 1968. These vessels are reaching or past their safe service life with capabilities that are inadequate for current USCG missions. The primary OPV mission functional areas and capabilities include: Port, Waterway and Coastal Security (PWCS); Search And Rescue (SAR); Drug Interdiction (DRUG); Migrant Interdiction (AMIO); Protect Living Marine Resources (LMR); Other Law Enforcement (OLE); and Defense Readiness (DR).
The selected OPV alternative is a low risk, low cost, knee-in-the-curve displacement monohull design on the costrisk-effectiveness frontier. This design was chosen because it provides a sharp increase in effectiveness with a minimal increase in cost at a low cost and risk level based on the MOGO results.
The emphasis of this paper is on the concept exploration design and requirements process.