As time – induces changes in shis such as hull deterioration (addiotional roughness), main egine operation (either reduces RPM in order to achieve affordable fuel costs) or power decrease due to main engine wear and tear certainly change oprimum propulsion from where it was originally designed.
Sometimes, the physical dimensions of the vessel such as lengthening or increased draught, change, in turn, the oprimum propulsion point.
In the light of the above, the propeller should be looked at end, after carefully establishing the change in load, proceed with the appropriate propeller modofication, which, in most cases, is done by removing a radial segment from each propeller blade.
As a result of the above, an increase in RPM and / or a decrease of exhaust gas temperature results after such an operation, allowing higher speeds and/ or more comfortable operation of the main engine, saving on spares and fuel.
Each case is looked at in its own merit. Design calculations are performed and drawings prepared for the precise steps, which are to be taken on the propeller.
Finally, on a suitable location or during dry- docking, the work is perfomed on the propeller by experienced personnel and proper supervision. Class approval is available at all stages of this work. |