Design of low cost, low emission marine propulsion systems
Ricardo marine propulsion experts used state-of-the-art computer aided engineering (CAE) software to evaluate the environmental and commercial performance of different marine propulsion system architectures under a range of different usage scenarios.
The work focused on the requirements of a typical harbour tugboat operating in a medium-sized European port. The general characteristics of the vessel were assumed to be a length of 35m, beam of 14m and draft of 5m, with a bollard pull of some 50 tonnes. Two alternative propulsion system configurations were considered for this vessel:
A high-efficiency conventional mechanical architecture, comprising two diesel engines powering respectively a port and starboard propeller by direct drive via a gearbox.
A hybrid electrical propulsion system based on two natural gas engine generator sets providing power to battery banks, with separate electric motors driving each propeller.
The study demonstrated the value of applying CAE simulation tools at the very earliest stages of vessel design or of repowering. From assessing the likely usage profile, the CAE tools allowed for the early assessment of detailed considerations of environmental performance, capital and operational expenditure requirements, and likely return on investment.