Lesson 4-5

What happens when you pass from fresh water to salt water?

• Draft increases

  Freeboard is reduced

• Shift of G

• Draft reduces

  Freeboard is increased

• Freeboard and draft both reduce

What is meant by the term freeboard?

• The amount of additional cargo a vessel can load.

• The distance from the water surface to the deck.

• The distance from the water surface to the top of the bulwark.

• The distance from the keel to the deck.

The water surface at the bow of a vessel is level with the top of the roman numeral V. What is the correct reading of this?

• 10 ft. 6 in. (3.20m)

• 10 ft. 0 in. (3.05m)

• 5 ft. 0 in. (1.52m)

• 5 ft. 6 in. (1.68m)

The forward draft of a vessel is 9 ft. 6 in. (2.87m) and the after draft is 9 ft. 11 in. (3.02m). What is the vessels mean draft?

• 9 ft. 6 in. (2.9m)

• 9 ft. 7 in. (2.92m)

• 9 ft. 8.5 in. (2.95m)

• 9 ft. 9 in. (2.87m)

Apart from its effects on stability, what effects on seaworthiness does a reduction of freeboard have?

• It provides a more stable platform for the crew.

• It subjects the ship to greater strains and risk of damage to deck structures.

• It increases the vessels reserve buoyancy.

• Greater initial stability.

What is the effect on stability by a reduction of freeboard?

• The initial stability is reduced.

• The maximum righting moment and the range of stability are both reduced.

• The initial stability is increased, but the range of stability is reduced.

• The vessel would take a small but permanent angle of heel.

The water level at the stern of a vessel is level with the middle of the roman numerals XV. (15) What is the correct reading of this?

• 15 ft. 6 in. (4.72m)

• 15 ft. 3 in. (4.65m)

• 20 ft. 3 in. (4.17m)

• 15 ft 0 in. (4.57)

What danger is possibly involved in the existence of the free surface of a liquid in a vessel?

• Damage might be sustained to the tank structure due to violent rolling.

• A significant reduction of the vessel’s stability.

• The rolling period of a vessel may be erratic.

• The loss of weight in the unoccupied portion of the tank.

What dangers are involved in overloading?

• A reduction of freeboard and adverse effect of this on stability.

• There is a greater possibility of structural damage by shipping heavy seas.

• Injuries to crewmembers by heavy seas.

• All of the above.

What is the general rule to be followed respecting tanks on a vessel and their bearing on the vessel’s stability?

• They should be as far as possible be kept either completely full or completely empty.

• They should be sounded daily and a record kept.

• They should be kept clean, with the pumping line always free.

• When filling tanks, overflow should not be allowed to take place thus avoiding unduly high hydrostatic pressure on tanks.