Abstract New environmental and business requirements mean that inland fleets need to be renewed; however, replacing an entire fleet is generally difficult and expensive. The modernisation of existing vessels may be a viable solution, particularly as this approach is aligned with the requirements for sustainable development and resource conservation. This paper describes a method for assessing the propulsive condition of an existing inland vessel, with a particular focus on the load on the main propulsion system during navigation of empty and loaded ships. One example is an inland pusher vessel, which is subjected to a preliminary analysis here to assess the potential for modernisation. The process of preparing for measurement is described, and the difficulties involved are identified. The analysis is based on measurements of the shaft torque, power and the ship’s speed. The recorded values for the propulsion power, the rotational speed of the propellers and the ship’s speed are presented in the form of graphs as a function of time. The results are given as propeller curves for the domains of the ship’s speed and the rotational speed of the propeller. Based on this analysis of the data, it was found that the propulsion system of a twin-propeller ship is unevenly loaded, with a difference between the loads on the port- and starboard-side propellers of up to 21% of the rated power of the engine. The ship was found to be unable to reach its design speed when loaded with cargo, and barely exceeded 9 km/h compared to the expected 10.5 km/h. Several options for modernisation are proposed.
Kowalak et al. (Wed,) studied this question.