Case study on the shaft line alignment for a 180 000 tdw bulk carrier vessel

Abstract

Alignment means the determination of displacements and breaks between two shafts and their elimination so that the geometric axes of the shafts become approximately collinear, and the deviations are within the permissible limits. This paper presents the methodological steps of the shaft line alignment (as a case study for a bulk carrier vessel of 180 000 tdw) through two classic approaches: with the help of a ruler and feeler gauge (templet) respectively with the help of dial gauge. Comparative analysis of the performances of the two methods, can provide essential information to an engineer in choosing the optimal option for alignment of the shaft lines both in the case of vessels in service and, mainly, in the case of new building’s. The originality of the work consists in carrying out the detailed calculations for displacements and breaks, with the graphical highlighting of the calculated values in the limit allowed intervals. Also, for each method are presented and commented the advantages and disadvantages.