Trimaran Hull Form Development for America's Marine Highways EXPRESS SERVICE Trailership
The paper describes the results of the hull form design of an innovative High Speed Trimaran Trailership (HSTT) as part of the fleet of trailerships, capable of carrying about 260 53’ trailers in the speed range of 25 up to 30 knots. The HSTT design requirements support America’s Marine Highways (AMH), an evolving national strategy. A commercial trimaran trailership has been justified for a 1000 nautical mile ocean route along the U.S. East Coast. This route would alleviate traffic on Interstate Highway Route I 95. This type of new express cargo ship could also provide military mobility capability in many inter and intra theater Sealift and Sea Base scenarios with a range of up to 9,500 nautical miles. The HSTT also creates a potential for the Army to lease necessary, flexible and capable ships for their missions. The HSTT is an arrangement of proven and innovative components: Trimaran hull forms; hybrid pod contra rotation propulsion; hybrid geared diesel/diesel electric machinery; multihull superstructure and advanced cargo handling systems. The Trimaran Trailership design is based on a series of design studies performed under Center for Commercial Deployment of Transportation Technologies (CCDOTT) sponsorship in the period of 1999-2009 and model tests in the Naval Surface Warfare Center Carderock Division’s David Taylor Model Basin in the 2000-2007 time frame. The refinement of the HSTT design requires hull form optimization with follow on resistance and self-propelled model tests, which are conducting at present time at MARIN. The hull form optimization presented in this paper involved the following activities: (1) a systematic investigation of multi-dimensional design space using first principle methods; (2) hydrodynamic optimization using a combination of non-linear free surface potential flow and boundary layer simulations; (3) a parametric hull model was used to conduct a formal exploration of the design space. The work was realized within the FRIENDSHIPFramework for CAE coupled to SHIPFLOW as the engine for Computational Fluid Dynamics. In parallel, the investigation was done with use of the FINE/Marine free surface RANS calculations. The paper includes the results of the hull form optimization and propulsion system selection for this innovative hybrid concept of HSTT concept. The paper describes the design aspects and applicability for commercial and sealift applications.