- 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.
LCF in fwd and trim by stern
$$Bodily \space sinkage \space = \space {{mass \space added} \over TPC} \space = \space {{110} \over 13} \space$$
$$=\:8.5\operatorname{\mathrm{cm}}\:=0.085m$$
$$Trim \space = \space {{m \times d} \over MCT_{1cm}}$$
$$ = \space {{110 \times (24 + 2.5)} \over 80}$$
$$Trim=36.43\operatorname{cm}=0.364m\:$$
Change in fwd draught:
$$d_{F}=\frac{-t}{L}\left\lbrack\frac{L}{2}-LCF\right\rbrack$$
$$=\frac{-36.43}{120}\left\lbrack\frac{120}{2}-2.5\right\rbrack$$
$$=-17.45\operatorname{cm}=-0.1745m$$
Change in Aft draught:
$$d_{A}=\frac{+t}{L}\left\lbrack\frac{L}{2}+LCF\right\rbrack$$
$$=\frac{+36.43}{120}\left\lbrack\frac{120}{2}+2.5\right\rbrack$$
$$=+18.97\operatorname{cm}=0.189m$$
New draughts:
$$D_{F}=5.5+0.085-0.175=5.41m$$
$$D_{A}=5.8+0.085+0.18=6.065m$$