Articles of The Transactions of KSRC

Full text article ( in russian)

Year	2015
Issue	374
Volume	4
Pages	5–10
Caption	Fast vessels with pumpjets
Authors	G. Kanevsky, S. Kaprantsev, A. Sokolov
Keywords	waterjets, fast vessel, hydrodynamic parameters
Summary	The paper describes the set of model tests performed on a fast vessel with displacement of ~3700 m3 so as to assess how the application of pumpjets with short water duct instead of propellers affects hydrodynamics. During replacement of propulsors, tilted shaft lines with their brackets were removed. To install waterjets, water ducts were made in the hull. Thus, the ship did not have a number of appendages, so with waterjets she showed ~5 % reduction in total towing drag. Open-water testing of waterjet models showed rather high efficiency, maximum 70 % at advance ratio of 1.5. For comparison: maximum efficiency of propellers was 66 % at the advance ratio of 1. Thus, in open-water, jet propulsors have ~6 % higher efficiency than propellers. Self-propulsion tests have shown that at full-speed (30 knots), the fast vessel with waterjets showed a drastic change in propulsor-hull interaction parameters, as compared to the data for propellers. In particular, wake fraction increased from –0.005 to 0.043. Thrust deduction coeffi-cient decreased from 0.09 to 0.034. Relative rotative factor is equal to 1 in both cases. Hull efficiency in these conditions grew from 0.905 to 1.008, i.e. by 11.4 %.
Rubrics	Naval architecture