Optimising ferry routes

In open waters, the skippers of passenger ferries have some leeway to plot a course that balances fuel efficiency, safety, and passenger comfort whilst still maintaining a tight schedule. This paper describes the seeking of an optimal ferry course for a 400t vehicular and passenger ferry. Numerical dynamic optimal control studies based on the vessel´s actual operating data, bathymetry and tidal streams showed that depth under keel was important in periods of slack water which fortuitously in this location happens to be adequately approximated by a simple straight line. During times of strong tidal streams, the optimal trajectory improved travel time by about 3.5% compared to the simple hooked curve course.