Tools for Support
CFD methods for trim matrix: The effect of trim on fuel consumption can be measured at the model scale in a towing tank or simulated at full scale using CFD. Many different speed and draft combinations can be simulated in a time efficient manner using fully viscous flow description analytical techniques. As a result, a “trim map” can be specified, where the optimum trim as a function of ship speed and draft are specified. (MariEMS 2017).
Dynamic trimming systems: These systems rely on a number of signals that are recorded whilst the ship is underway. The signals provide an indication of the ship's actual trim and some performance aspects of the vessel. Then the system uses analytical or artificial intelligence methods to forecast an optimum trim. Similar to “trim map” as explained above, this makes a good deal of theoretical sense but the actual effectiveness has yet to be established. Dynamic trim optimization includes collecting and monitoring real-time data of propeller thrust and manoeuvring rudder angles, weather conditions and sea-state (MariEMS 2017).
Loading computers: The change in ship trim is achieved via cargo load planning and a ballasting plan when in port. When underway, the shift of ballast water and fuel between their relevant tanks may be used to adjust trim. During loading, occasionally there are limitations for achieving optimum trim due to the level of cargo and loading limitations that may not allow additional ballast for a proper trim. Nowadays, loading computers provide additional functionality for the representation of trim, optimal trim and also loading options to achieve the optimal trim. Trim linked to a loading computer helps the deck officers to achieve a better loading plan and optimal trim (MariEMS 2017).
There is a direct method that consists in measurement the power developed for the main engine and to change the trim to get the best trim with the minimum power and minimum fuel consumption (MariEMS 2017).