Özsayan S., Taylan M.

BRODOGRADNJA, vol.70, no.2, pp.135-153, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Review
  • Volume: 70 Issue: 2
  • Publication Date: 2019
  • Doi Number: 10.21278/brod70207
  • Journal Name: BRODOGRADNJA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.135-153
  • Istanbul Technical University Affiliated: Yes


The classical method (namely inclining experiment) has been used to estimate the vertical center of gravity (VCG or more often KG) of ships for many years. This method is based on the assumption that the metacenter is unchanged in the calculation of KG when the vessel is heeled. However, ships built today have knuckles, chines, dead-rise which may give rise to excessive change in the water-plane. The location of the metacenter is changed on these vessels when heeled. Therefore, determination of the vertical center of gravity may be somewhat erroneous. In this study, three different methods based on the assumption of unchanged metacenter have been examined. Employing the Graphical method, Polar method and Generalized method, the KG values of all vessels can be calculated without any dependence on the metacenter. The three methods mentioned in this study were studied and applied on ten different ships. Furthermore, the results from the classical method compared with those obtained from the recently developed methods. Based on this comparison, it is observed that the new methods developed have similar results to the classical method. Therefore, these methods may be a good alternative to the inclining experiment in the future. Moreover, uncertainty analyses have been performed for the results obtained from the classical method just to realize if there are any critical GM values within the margin of error.