4.1.1
Length (L) is the length measured
between the aft and forward perpendiculars.
4.1.2
Midship point is the point
on the centreline of a ship midway between the aft and forward perpendiculars.
4.1.3
Draught (T
a
) is
the draught at the aft perpendicular.
4.1.4
Draught (T
f
) is
the draught at the forward perpendicular.
4.1.5
Mean draught (T
m
) is defined as T
m = (T
a + T
f)/2.
4.1.6
Trim (
) is defined as 
= (T
a - T
f).
4.1.7 ∆ is the full load displacement of
the ship (tonnes).