Host And Shafting Alignment Installation

The quality of shaft alignment, is of vital importance in ensuring the long term appropriate running of shafting system and shortening the construction period of shipbuilding, also crucial in keeping the sailing vessel in the set course. A common recognized method for the shaft alignment, is to set up a physical model, and appropriately locate each bearing in compliance with the required bearing load, stress and shear force and slop etc, so as to fix the shaft with the curve line as required and obtain a right distribution of bearing load.During the shipbuilding in major shipyards worldwide, plenty of problems are generated out of shaft alignment, which results in the over-tolerance of main engine crank shaft, high temperature of bearing and excessive vibration. The element leading to problems could be extremely complicated, for instance, insufficient consideration during the model setup; certain affecting elements vary with different types of ship, like the ship hull deformation, shaft vibration and reinforcing hardness and so on; inadequate accuracy control and errors during the construction. All of the problems shall be dealt with certain scientific method and processed in the right manner.This article states the applicable method for the shaft alignment calculation and rationale in element process, setup of model and alignment calculation. Based on the handling of problems shown in 110, 000dwt product carriers, built by Dalian New Shipyard for Denmark, and the installation procedure of VLCC for Iran, a detailed description is presented on the installation technical and problems disposals of main engine and shafting system. In this article, the way of calculation, installation and problem handling, quoted of Sulzer, the main engine maker, and classification societies like Lloyd's, DNV and BV are referred.