International Shipbuilding Progress - Volume 7, issue 70

Authors: van Manen, J.D. | Kamps, J.

Article Type: Research Article

Abstract: The boom in high-powered tanker-building after the last war led to many cases of vibration troubles and cavitation-erosion damage on the propeller blades. For this reason an extensive systematical investigation into the effect of shape of afterbody on propulsion has been carried out at the NSMB. The basic ship type was a 39,000 ton deadweight tanker, the maximum size that can pass the Suez Canal in loaded condition. The variations in afterbody which were studied follow: I–Optimum shape from an efficiency point of view, based on statistical data of the NSMB (moderately U-shaped sections). II–Extremely V-shaped sections. III–Extremely U-shaped sections. …IV–Cigar-shaped stern with Mariner rudder arrangement (Hogner afterbody). V–Extremely U-shaped sections combined with a screw in a nozzle. VI–Extremely U-shaped sections combined with two screws, each fitted in a nozzle, one above the other. VII–A twin-screw arrangement. Resistance and self-propulsion tests were carried out with four- and five-bladed propellers in the loaded and ballast condition. Wake measurements with pitot tubes and flow observations with tufts have been made. Cavitation tests in the tunnel with adjustable frow were carried out. Finally the variations in the propeller thrust and torque during one revolution were recorded and analyzed. Show more

DOI: 10.3233/ISP-1960-77001

Citation: International Shipbuilding Progress, vol. 7, no. 70, pp. 231-252, 1960

Authors: Teasdale, J.A.

Article Type: Research Article

Abstract: There has been much public interest recently in the possibility of the underwater carriage of cargo but, although submarine cargo vessels are now technically feasible with the use of nuclear power, they are not likely to be used commercially for normal trades unless they can show an economic advantage. The purpose of this paper is to discuss the likely characteristics and performance of a submarine tanker and to compare it with a surface tanker of the same deadweight, both vessels being propelled by nuclear power. At normal speeds the optimum submarine form would have a slightly lower resistance than …the surface vessel but the margin is such that the saving in annual fuel bill is most unlikely to offset the additional cost of a submarine and the operational difficulties attendant on its use. Operation at higher speeds may become economic if nuclear fuel and machinery costs are reduced to low values, but only when the surface vessels have reached the limit of development for high speed operation is the possibility of submarine cargo vessels likely to be given serious consideration. Show more

DOI: 10.3233/ISP-1960-77002

Citation: International Shipbuilding Progress, vol. 7, no. 70, pp. 253-260, 1960

Authors: Vossers, G.

Article Type: Research Article

DOI: 10.3233/ISP-1960-77003

Citation: International Shipbuilding Progress, vol. 7, no. 70, pp. 261-279, 1960