THE DIAGRAMS OF SHIPS ICE PROPULSIVE QUALITY

Abstract

The diagrams of ships ice propulsive quality allowing to determine all relevant parameters (power consumption, propeller RPM, movement speed and propulsion thrust) are described in the paper. These diagrams can be used to calculate above-mentioned ice propulsive quality parameters for the scenarios of high loads on propulsion system at low advance coefficients, like ice navigation and towing operations. It is pointed out that previously this calculation was impossible because of wake fractions tend to “minus infinity”. To overcome this challenge, an alternative (mooring) system of interaction coefficients briefly presented in this paper and enabling all required calculations, is developed and applied. The results of these calculations are presented in the form of ice propulsive quality diagrams that clearly and conveniently display the entire volume of the calculation data. It has been shown that ice propulsive quality diagrams can be easily added with the environmental data for usability. In the diagram given in this paper, the environmental parameter is the thickness of ice that the ship has to overcome. The possible practical applications for these diagrams, for instance ice resistance assessment during full-scale trials, are discussed in the paper. It is highlighted that the data contained in the ice propulsive quality diagrams are approximate. The possibility of using other environmental parameters is also discussed in the paper.