A propeller is engineered to last throughout the lifetime of a vessel. During its operation factors, such as biological growth on the hull and a change in operating conditions, can result in the relationship between the propeller and the engine being disturbed.
When the effect becomes too serious, engine overload is inevitable. In most cases, this is noticeable by black smoke emerging from the exhaust pipes. This results in higher fuel consumption and increased wear to the pistons, liners and valves, and with that higher maintenance costs. It is estimated that 20% of the world’s fleet suffers from heavy running propellers, whilst the solution by means of modification is within reach and has proven to be very effective.
The propeller is designed with a certain sea margin and/or light running margin to ensure efficient performance, even when the vessel is experiencing increased resistance like heavy weather conditions. When the propeller is heavy running, the rotation rate at service speed is reduced significantly. This means that full power absorption during conditions where there is increased resistance, or even during trials, cannot be realized normally. This could even affect the vessel’s speed during service conditions.
Wärtsilä is a global leader in advanced technologies and complete lifecycle solutions for the marine and energy markets. By emphasising sustainable innovation and total efficiency, Wärtsilä maximises the environmental and economic performance of the vessels and power plants of its customers.