Ship Speed-Power Performance Assessment

Abstract

The speed/power characteristics of ships have always been at the core of ship design. To prove contractually agreed values, speed trials are conducted by the yard prior to delivery of the ship to the owner. In the past schedule integrity of the vessel was often the most important factor for the speed requirement. Today, owners and operators are keen to reduce fuel consumption to decrease operational costs. So far a variety of methods for conducting and analyzing speed/power trials have been used by shipyards. With the assistance of the Sea Trial Analysis-Joint Industry Project, ITTC developed guidelines for the execution and analysis of speed/power trials compliant with IMO EEDI. The need to reduce fuel costs and exhaust gas emissions including the upcoming environmental regulations such as EEOI by IMO urge for reliable monitoring of ship performance in service conditions. This requires accurate information of the speed through water. Although the speed log is one of the oldest instruments on board it is not considered the most reliable one. Results of an extensive monitoring campaign on board a 1800 TEU container vessel equipped with six speed logs within SPA-JIP will be presented. The state of art of performance monitoring will be presented.

Combining Optimization and Simulation for Designing a Robust Short-Sea Feeder Network

“…Since the vessel speed is a function of propulsion power and total resistance, and given that the propulsion power is assumed to be constant, higher waves and winds due to harsh weather cause an increase in total resistance, which results in a decrease of vessel speed. In our model, resistance from waves is calculated according to the STAwave-1 method [39].…”