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Boat & Combatant Craft Electric Drive Propulsion System


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Renewable Energy Generation and Storage OBJECTIVE: Develop electric drive propulsion technology for aboard boat and combatant craft to add redundancy, increase fuel economy, reduce signature, and increase payload capacity at loiter and low speeds. DESCRIPTION: Small vehicle electric drive propulsion technology is prevalent in other industries especially automotive. However, a capability that is marinized and meets the mission requirements of U.S. Navy boat and combatant craft does not exist. Boats and Combatant craft operate eighty (80) percent of the time at slow and loiter speeds while the propulsion systems are designed for higher cruise speeds. Engines rated for cruise speeds tend to be very inefficient at loiter speeds resulting in inefficient fuel consumption. By introducing electric drive propulsion, boats and combatant craft can operate on electric power generated by a group of smaller generators or engines operating at an efficient power and fuel consumption, thereby reducing total ownership cost instead of having large diesel engines operating in non-ideal conditions. Total ownership cost is reduced through reduced fuel consumption and less/lower cost maintenance. Less maintenance is achieved through operating an engine at a lower speed rating or at a more optimum power rating and lower cost is achieved by having smaller more operator-accessible and maintainable systems. Additionally, electric propulsion at lower boat speeds can decrease the level of sound emitted from the boat, reducing a boat’s noise signature and increasing its tactical advantage. Finally, there is added redundancy with multiple means to generate electrical power to maintain performance of the craft. The technology shall be evaluated against existing boat specifications, original manufacturer data, and existing life cycle operating data. A marine configured electric drive propulsion system does not exist in the operational profile required for 425 – 550hp at an engine shaft speed range of 500-4000 rpm at the output of the marine gear as well as required boat endurance and range for boats and combatant craft operated by DoD and U.S. Navy. PHASE I: Develop a concept for a marine configured electric drive propulsion system for a relevant vessel similar to a U.S. Navy 30-40 foot Patrol Boat that meets the requirements in the Description. Demonstrate the feasibility of the operational concept via physics-based modeling and simulation. Within the feasibility study, define the components of the propulsion system and hull, mechanical and electrical interfaces required, the power control management system as well as functional design concepts of the system. Provide a preliminary concept design and an associated component validation plan. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II. PHASE II: Develop and deliver a prototype operational electric drive propulsion system capable of being integrated with a US Navy 30-40 foot Patrol Boat. Evaluate the prototype to determine its capability in meeting the performance goals defined in the Phase II SOW and the Navy requirements for the 30-40 foot Patrol Boats. Demonstrate system performance through prototype evaluation and testing, modeling, and analysis. Evaluate results and accordingly refine the propulsion system concept. Ensure that the prototyped hardware clearly shows a path to development of a sea worthy hardened system. On request, the prototype model is to be made available for Government demonstration or testing. Prepare a Phase III development plan to transition the technology to Navy use. PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the electric drive propulsion system to Navy use. Support the Navy in transitioning a fully hardened electric drive propulsion system for sea trials to be demonstrated on a relevant vessel. Ensure that the system passes an underway test to be developed for the defined test platform. Support for participation in fleet demonstration is aimed at transition and integration of the system into the US Navy Patrol Boat Fleet. A propulsion system of this type should benefit working craft in the fishing, oil, or research industries operating in the open water environment. REFERENCES: 1. Tamunodukobipi, Daniel; Samson, Nitonye and Sidum, Adumene “Review of All-Electric and Hybrid-Electric Propulsion Technology for Small Vessels”, Nova Scotia Boat Builders Association. 27 March 2015; 2. Naval Surface Warfare Center. Carderock Division, Combatant Craft Division; US Navy 30-40 foot Combatant Craft Hybridization Specification KEYWORDS: Electric Drive Propulsion Systems; U.S. Navy 34-ft Patrol Boat; U.S. Navy 40-ft Patrol Boat; Mine Counter Measures Operations; Force Protection Operations; Distributed Maritime Operations and Littoral Operations in a Contested Environment
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