International Shipbuilding Progress - Volume 11, issue 113

Authors: Wereldsma, R.

Article Type: Research Article

Abstract: The pattern of the material stresses in the root of a blade of a propeller operating behind a single screw tanker has been determined by means of strain gauges. The measured stresses agree with those calculated according to different existing methods. In the root of the blade a fourfold safety margin against fatigue exists.

DOI: 10.3233/ISP-1964-1111301

Citation: International Shipbuilding Progress, vol. 11, no. 113, pp. 3-16, 1964

Authors: Bakker, A.R.

Article Type: Research Article

Abstract: Methods are discussed which have been developed for the computer X-1 of the N.S.M.B. for carrying out automatic calculations in naval architecture. It is shown that a very satisfactory degree of accuracy can be obtained with 23 ordinates ( 0 , 1 2 , 1 , 2 , … … … 18 , 19 , 19 1 2 , 20 ) . Besides theoretical discussions, concerning the errors which occur, the influence on the results of variation of the number of sections and points measured is investigated.

DOI: 10.3233/ISP-1964-1111302

Citation: International Shipbuilding Progress, vol. 11, no. 113, pp. 17-28, 1964

Authors: Mayer, G. | Balajiva, K.

Article Type: Research Article

Abstract: Tensile and impact data are presented for cast stainless steels tested at temperatures between 20°and –1960°C. The steels investigated were based on the 18Cr-8Ni, 18Cr-8Ni-Nb, 18Cr-10Ni-3Mo and 18Cr-10Ni-3Mo-Nb types. The influence of variation, in carbon and nickel contents on the properties and microstructure of each type of steel was examined. Increasing the carbon content within the range 0.05–0.1% lowered the impact properties of all the steels except the Cr-Ni-Mo types, in which carbon was deleterious only if present in amounts greater than about 0.1%. Optimum nickel contents in relation to impact properties are indicated for the respective types of steel.

DOI: 10.3233/ISP-1964-1111303

Citation: International Shipbuilding Progress, vol. 11, no. 113, pp. 29-35, 1964

Authors: Kleiner, A.

Article Type: Research Article

Abstract: The crankshaft of every reciprocating marine engine and the propeller shafting driven by it are subject to axial as well as torsional vibration. The larger the number of cylinders and cranks in the engine, the more pronounced this axial vibration becomes. It is caused both by the radial forces acting on each crank and by the periodic thrust of the propeller. In the shafting of a cargo vessel of 12,600 gross tons propelled by a twelve-cylinder two-stroke diesel engine of 18,000 h.p., a troublesome fourth-order resonance of the axial vibration was reduced by about two-thirds by opposing the excitation from …the propeller to that from the diesel engine. Rotation of the propeller relative to the engine through an angle which was fixed to an accuracy of a few degrees was quite sufficient to produce a substantial improvement. Analysis of the vibration measurements in three different relative positions of propeller and diesel engine finally proved that the propeller had been turned into its optimum position. No further improvement was possible. Show more

DOI: 10.3233/ISP-1964-1111304

Citation: International Shipbuilding Progress, vol. 11, no. 113, pp. 36-41, 1964