International Shipbuilding Progress - Volume 10, issue 104

Authors: van Manen, J.D. | Bakker, A.R.

Article Type: Research Article

Abstract: Sparenberg’s lifting surface theory for ship screws was programmed for the digital computer X 1 of the Netherlands Ship Model Basin. The results of systematic calculations for symmetric blades and pressure distributions can be interpreted as “lifting line to lifting surface correction” factors. These factors were plotted in a diagram for different pitch ratios, numbers of blades, blade area ratios and three types of radial load distributions. Also the effect of skew back and asymmetric chordwise pressure distributions has been considered.

DOI: 10.3233/ISP-1963-1010401

Citation: International Shipbuilding Progress, vol. 10, no. 104, pp. 111-118, 1963

Authors: Burrill, L.C. | Emerson, A.

Article Type: Research Article

Abstract: Results are presented for a four-bladed .60 expanded-area ratio merchant-ship propeller series tested in the cavitation tunnel in the Department of Naval Architecture and Shipbuilding, King’s College, Newcastle upon Tyne, over a wide range of advance coefficient and at cavitation numbers from the low values corresponding to twin-screw passenger-liner propellers up to the higher values for a large single-screw cargo ship. The variations studied are pitch-ratio, distribution of area and distribution of pitch, and, to some extent, changes in blade-section shape, and the paper includes design charts in the usual B p − δ …form, together with simple cavitation diagrams derived from the test results. Most of the work has been carried out in a uniform stream, but the final section relates to tests made in a radially variable stream velocity. The paper also considers specific designs at each end of the merchant-ship range; four- and five-bladed propellers for a passenger liner; five- and six-bladed propellers for a large tanker. Som observations of variable-wake tests are given. Show more

DOI: 10.3233/ISP-1963-1010402

Citation: International Shipbuilding Progress, vol. 10, no. 104, pp. 119-131, 1963

Authors: Townsin, R.L.

Article Type: Research Article

Abstract: The paper describes the results of pressure measurements on the hull of a 1/50th scale Victory model carried out in the Research Laboratories of the Department of Naval Architecture and Shipbuilding at King’s College, Newcastle upon Tyne. The purpose of the measurements was to obtain the skin friction resistance by the deduction of the pressure resistance from the total resistance. Pressures at one hundred holes disposed over the hull were measured simultaneously with total resistance, wave profile, speed and trim. Records were taken at twenty-five speeds between the Froude numbers 0.21 and 0.28. The results are in accord …with previous work in demonstrating that the friction resistance is greatly in excess of flat plane formulations, but the present results give larger form factors which vary with speed. The results give an indication of separation at the higher speeds. Show more

DOI: 10.3233/ISP-1963-1010403

Citation: International Shipbuilding Progress, vol. 10, no. 104, pp. 132-145, 1963