MCA CoC Ship Stability 2

Question 1

What information does the GZ curve (curve of statical stability) provide to the Master?

Accepted Answer

The righting lever at different angles of heel, showing range of stability, maximum GZ, and angle of vanishing stability

Answer

The vessel's speed at different draughts

Answer

The vessel's fuel consumption at varying displacements

Answer

The vessel's trim at different loading conditions

Question 2

Under the MCA's stability criteria (based on the IMO Intact Stability Code), what is the minimum required GM for a cargo vessel in the departure condition?

Accepted Answer

0.15 metres

Answer

0.05 metres

Answer

0.50 metres

Answer

1.00 metre

Question 3

What is 'angle of loll' and how does it differ from a list caused by asymmetric loading?

Accepted Answer

Angle of loll occurs when GM is negative and the vessel heels to find a new equilibrium; list is caused by G being off-centreline due to weight distribution

Answer

Angle of loll is a permanent structural deformation; list is temporary

Answer

Both are the same condition with different names

Answer

Angle of loll only occurs in beam seas; list occurs in calm water

Question 4

When a vessel grounds at low water on an even keel, what is the primary stability concern?

Accepted Answer

The upward ground reaction force reduces displacement, effectively raising G above M and potentially causing the vessel to heel dangerously

Answer

The vessel's draught will increase

Answer

The hull will immediately flood through bottom damage

Answer

The cargo will shift due to the impact

Question 5

What is the 'moment to change trim by one centimetre' (MCTC or MCT1cm) and how is it used?

Accepted Answer

The moment required to change the vessel's total trim by one centimetre — used to calculate the effect of loading, discharging, or shifting weights on trim

Answer

The amount of fuel needed to alter the vessel's speed by one knot

Answer

The force needed to turn the rudder by one degree

Answer

The weight needed to increase draught by one centimetre

Question 6

A vessel displacing 10,000 tonnes has KM = 8.5 m and KG = 7.2 m. A weight of 500 tonnes is shifted vertically upward by 4 metres. What is the new GM?

Accepted Answer

1.10 metres

Answer

0.80 metres

Answer

1.30 metres

Answer

1.11 metres