Free Surface effect (Quiz)

What is the free surface effect?

• The friction between hull and water

• The movement of cargo on deck

• The shifting of liquid inside a partially filled tank

• The loss of speed due to hull shape

Which condition produces the greatest free surface effect?

• Tank is full

• Tank is empty

• Tank is partially filled

• Tank has solid cargo

What happens to the ship’s center of gravity when free surface effect occurs?

• It shifts upward and laterally

• It remains in the center

• It moves downward

• It disappears

Which tank characteristic increases the severity of free surface effect

• Narrow width

• Low height

• Wide breadth

• Sloped bottom

What does “FSM” stand for in stability calculations?

• Fuel Safety Margin

• Free Surface Movement

• Free Surface Moment

• Forward Stability Mark

Free surface effect primarily reduces which of the following?

• Draft

• Trim

• Buoyancy

• Metacentric height (GM)

Which method is not effective in reducing the free surface effect?

• Keeping tanks full

• Dividing tanks with longitudinal bulkheads

• Keeping tanks partially filled

• Emptying tanks completely

Why are longitudinal bulkheads used in tanks?

• To reduce sloshing and FSM

• To increase cargo space

• To store spare parts

• To maintain tank temperature

What does Free Surface Correction (FSC) do in stability calculations?

• Adds buoyancy

• Adds trim

• Subtracts from GM

• Increases draft

In which situation would the free surface effect be least dangerous?

• In a high-speed turn

• During rough sea navigation

• With all tanks pressed up

• With wide tanks partially filled