![]() As we shall show in Chapter 9, waves perpendicular or oblique to the ship velocity influence the values of cross-curves and can cause a very dangerous effect called parametric resonance. Modern computer programmes for Naval Architecture include this option. More recently, the 2008 IMO code for intact stability recommends to calculate the cross-curves with the “free trim” option. The old stability regulations, BV 1033, of the German Navy required, indeed, the calculation of the cross-curves at the trim induced by heel. Jakić (1980) has shown that trim can greatly influence the values of cross-curves and, therefore, that influence should be taken into account. Therefore, cross-curves calculated at constant trim may not represent actual stability conditions. ![]() ![]() If the centre of buoyancy moves along the ship, while the position of the centre of gravity is constant, the trim changes too. It happens so because at large heel angles the waterplane ceases to be symmetric about the centreline. (2.28), developed in Chapter 2, shows that the longitudinal position of the centre of buoyancy changes if the heel angle is large. This approach was justified before the appearance of computers and Naval-Architectural software. Once it was usual to calculate the cross-curves of stability at constant trim, i.e. Adrian Biran, Rubén López-Pulido, in Ship Hydrostatics and Stability (Second Edition), 2014 5.4 The Influence of Trim and Waves
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |