7...-Naval-Architecture-and-Ship-Construction-Including-Damage-Control-Damage-Control.ppt - Function 1 Marine Engineering at the Management Level

# 7...-Naval-Architecture-and-Ship-Construction-Including-Damage-Control-Damage-Control.ppt

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Module 3 1 Function 1: Marine Engineering at the Management Level 1.1.6Naval Architecture and Ship Construction Including Damage Control
Module 3 2 Function 1: Marine Engineering at the Management Level Center of Gravity (G): that point at which all the vertically downward forces of weight of the vessel can be considered to act; or it is the center of the mass of the vessel. 6.1 Basic Stability and Trim G is the resultant of all vertical downward forces of gravity
Module 3 3 Function 1: Marine Engineering at the Management Level Center of Buoyancy (B): that point at which all the vertically upward forces support (buoyancy) can be considered to act; or, it is the center of the volume of the immersed portion of the vessel. B resultant of all vertical upward forces of buoyancy B is the center of gravity of the immersed portion of the vessel 6.1 Basic Stability and Trim
Module 3 4 Function 1: Marine Engineering at the Management Level Transverse Metacenter (MT): point through which the center of buoyancy (B), acts vertically upwards as the vessel is inclined and (B) shifts towards the low side. The same displacement; the same angle of inclination but G moves, transverse metacenter (M) and the equilibriums 6.1 Basic Stability and Trim
Module 3 5 Function 1: Marine Engineering at the Management Level Metacentric Height (GM): is the measure of the initial stability of a vessel or it is the vertical distance between the ship’s center of gravity and the initial transverse metacenter (M). GM as a Function of GZ 6.1 Basic Stability and Trim
Module 3 6 Function 1: Marine Engineering at the Management Level 6.1 Basic Stability and Trim Heel (roll) is caused by external forces to the ship. - Ocean waves cause an external force on the ship that start the ship rolling and keep it rolling. Effects of Listing and Heeling List is caused by internal forces. - may have been created by poor loading policies, - by shift of cargo or ballast in heavy weather, or - by unsymmetrical flooding after damage. In any of these cases, the list will be attributed either to a negative initial stability (a negative GM) or a condition in which G is off the centerline. Either way, the ship will oscillate about this angle of list instead of about the vertical.
Module 3 7 Function 1: Marine Engineering at the Management Level 6.1 Basic Stability and Trim It merely means that the vessel does not have any initial stability, and that she will incline to an angle where B has moved far enough toward Dangers of a Ship Having Negative GM If the center of gravity lies above the transverse metacenter (G above M), the vessel is in state of unstable equilibrium , that is, she possesses a negative GM. There is no tendency for the vessel to right herself at small angles of inclination.