This paper will discuss the conversion of the US Navy LHD assault ship from conventional steam propulsion to gas turbine mechanical drive with all electric auxiliaries. The LHD 8 will provide gas turbine mechanical drive and electric propulsion via Controllable Pitch Propellers (CPP) in a Combined Operation Diesel Electric or Gas Turbine (CODLOG) configuration. The primary propulsion is from gas turbine engines with an auxiliary electric drive to provide economical low speed operations while the ship is operating in the littoral zone. The paper will discuss how the gas turbine drive in concert with an electric “loiter” motor drive will be used to provide the most efficient drive combination for each operating scenario. The paper will also discuss the process, trade-offs, and constraints placed on the designers of incorporating a new propulsion plant into an existing ship design. Interfaces with other ship systems presented significant challenges. The text presents the constraints and issues involved in the design process by addressing all major design impacts and significant design concerns. Since the Navy first introduced the General Electric LM2500, the standard gas turbine installation has changed very little and all major surface combatants since the early 1970s have utilized a very similar design. The paper will discuss how the LM2500+ installation on LHD 8, the first of its kind in a military application, will capitalize on the existing design while at the same time changing to meet new requirements, standards and regulations. The paper will also discuss the changes brought about by adopting commercial practices and standards and capitalizing on commercial experiences particularly in areas such as engine qualification.

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