Practical 1.2 Buoyancy

In order to use the appropriate formulae, the following quantities must be known:

I_ws : the second moment of area of the water plane shape about the axis of least stability;

V : the submerged volume;

GB : the distance between G, the centre of gravity of the entire vessel, and B, the centre of the submerged volume V

Metacentric Height, GM = I_ws/V. ± GB

IMPORTANT: SHOW ALL CALCULATION STEPS

TASK 1: Determine the Metacentric Height of each vessel using the field technique.

TASK 2: Determine the Metacentric Height of each vessel using the formula

TASK 3: Comment on discrepancies between the results given by the two methods for finding Metacentric Height.

Supporting Information

The ‘field’ technique employs a buoyancy expression which is valid for small angles of list:

Where wj is the jockey weight

W is the submerged weight

dx is the distance from the centre

θ is the stable angle (radians)