Question

(a) Define longitudinal center of gravity (LCG) and longitudinal centre of buoyancy (LCB) (6)

(b) A vessel, when floating at a draught of 3.6 m has a displacement of 8172 tonne, KB 1.91 m and LCB 0.15 m aft of midships. From the following information, calculate the displacement, KB and position of the LCB for the vessel when floating at a draught of 1.2 m. (10)

Draught: 1.2, 2.4, 3.6

TPC: 23, 24.2, 25

LCF from midships: 1.37F, 0.76A, 0.92A

Answer 1

Part (a)

Longitudinal Centre of Gravity (LCG):

The Longitudinal Centre of Gravity (LCG) is the point along the length of the vessel where the total weight of the ship is considered to act vertically downward.
It represents the balance point of the ship's weight distribution and is measured as a distance forward or aft of the midship.

Longitudinal Centre of Buoyancy (LCB):

The Longitudinal Centre of Buoyancy (LCB) is the point along the length of the vessel through which the total buoyant force, acting vertically upward, is considered to act.
It represents the balance point of the underwater volume of the ship and is also given as a distance forward or aft of the midship.

✓ Verified Model Answer (Text Solution)

Longitudinal Centre of Gravity (LCG):