Operation Guidance
The current industry practice points to the fact that in the great majority of cases, even keel operation (zero trim) is the normal practice. This generally may represent the optimal trim for ships with high block coefficients and non-pronounced bulbous bow (e.g. bulkers and tankers). These ships are not normally operating at very high speeds; thus having a relatively lower wave making resistance. In ships with a slimmer body and higher speed, the impact of trim on performance could be significant. In particular, the trim may have impact on performance of the bulbous bow, and thereby wave making resistance. This will signify that these types of ships are more sensitive to trim and therefore greater care should be exercised with trim optimization. With the recent development in energy efficiency regulations, more companies have opted out to establish their ships’ optimum trims; with the extensive use of CFD capabilities for this purpose (MariEMS 2017).