MCA Certificate of Competency Ship Stability and Trim Questions and Answers

Question 1

A vessel has a negative initial metacentric height (GM) when upright. What is the resulting condition of the vessel called?

Accepted Answer

Angle of loll

Answer

Stiff

Answer

Tender

Answer

Angle of list

Question 2

According to the MCA's interpretation of the International Load Line Convention, which of the following is a key intact stability requirement for a general cargo ship?

Accepted Answer

The area under the GZ curve up to 40° must be at least 0.09 metre-radians.

Answer

The initial metacentric height (GM) must not be less than 0.30m.

Answer

The maximum righting arm (GZ) should occur at an angle of heel not less than 45°.

Answer

The angle of heel due to turning must not exceed 15°.

Question 3

A ship is loading a timber deck cargo and intends to sail with a timber load line. Which of the following stability criteria is specifically required under UK regulations for this condition?

Accepted Answer

The maximum righting arm (GZ) must be at least 0.25m.

Answer

The initial metacentric height (GM) must not be less than 0.25m.

Answer

The angle of heel due to grain shift must not exceed 12°.

Answer

The area under the GZ curve up to 30° must be at least 0.08 metre-radians.

Question 4

A vessel has several slack double-bottom tanks. What is the primary effect of the free surface of the liquid in these tanks on the vessel's stability?

Accepted Answer

A reduction in the righting arm (GZ) at all angles of heel.

Answer

An increase in the effective metacentric height (GM).

Answer

A virtual reduction in the height of the centre of gravity (KG).

Answer

A decrease in the vessel's displacement.

Question 5

When calculating a ship's trim, the Moment to Change Trim by one Centimetre (MCTC) is a critical value. Which of the following factors primarily determines the MCTC?

Accepted Answer

The vessel's displacement and longitudinal metacentric height (GML).

Answer

The vessel's KG and KM.

Answer

The longitudinal position of the centre of gravity (LCG).

Answer

The transverse moment of inertia of the waterplane.

Question 6

A UK-flagged vessel is loading bulk grain. According to the International Grain Code as enforced by the MCA, what is the maximum allowable angle of heel due to grain shift?

Accepted Answer

12 degrees or the angle of deck edge immersion, whichever is less

Answer

10 degrees

Answer

15 degrees

Answer

The angle at which the deck edge is immersed