engleski

Measurement of hull deflections for reliable propulsion system alignment using digital photogrammetry

The ship propulsion system alignment is important activity for quality and reliable operation. The alignment procedure is under classification society rules, which determine guidelines for design, calculation and installation of the propulsion system elements. A part of the classification society guidelines is related to measurement of the hull deflections, which could be caused by ship loading condition, temperature variation affecting the propulsion shafting system and launching. Hull deflections have a dominant influence on the propulsion system elements when a ship is in service. Changes in the elastic line shape of the intermediate shafts occur, resulting in the irregular position of the intermediate shafts in bearing. Althought, measurement of hull deflections is rather complex task, they should be predicted in the alignment calculations. Classification societies conduct extensive research into ship hull deflections occurring with different ship types and sizes. Different measurement methods have been used in the research, and one of the research goals has been to define a reliable measurement method. The hypothesis proposed in this paper is that hull deflections can be reliably measured by using the photogrammetric method. The paper presents use of digital photogrammetry for measurement of the hull deflections. Theory and measurement equipment of digital photogrammetry are presented. The automated photogrammetric system TRITOP, presented in the paper, is used for 3D measurements, results processing and analysis. Measurement procedure and results are illustrated by an example. The conclusion contains review of the measuring method applicability, advantages of the digital photogrammetry and suggestions for the propulsion alignment development.

Measurement; Propulsion system; Photogrammetry

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