AB Ship Construction and Cargo 3 — Questions and Answers
Question 1: What is meant by 'GM' in ship stability terminology?
- The distance from the keel to the center of gravity
- The metacentric height — the distance between the center of gravity and the metacenter (Correct answer)
- The distance from the waterline to the main deck
- The gross measurement of cargo capacity
Correct answer: The metacentric height — the distance between the center of gravity and the metacenter
GM (metacentric height) is the vertical distance between G (center of gravity) and M (metacenter), and it is the primary measure of initial stability.
Question 2: Which type of ship construction uses a series of transverse frames as the primary structural support?
- Longitudinal framing system
- Composite framing system
- Transverse framing system (Correct answer)
- Isherwood framing system
Correct answer: Transverse framing system
The transverse framing system uses closely spaced transverse frames (ribs) as the primary structural members, common in older and smaller vessels.
Question 3: A 'tween deck' is BEST described as:
- A deck located between the main deck and the keel
- A deck located between two adjacent main cargo decks within a hold (Correct answer)
- The weather deck between the bow and bridge
- The platform deck in the engine room
Correct answer: A deck located between two adjacent main cargo decks within a hold
A tween deck is an intermediate deck inside a cargo hold, dividing the hold into upper and lower compartments to allow separate cargo stowage.
Question 4: What is the primary purpose of double-bottom tanks?
- To carry deck cargo
- To serve as ballast tanks and provide structural protection to the inner bottom (Correct answer)
- To store emergency generator fuel exclusively
- To house life-saving appliances
Correct answer: To serve as ballast tanks and provide structural protection to the inner bottom
Double-bottom tanks serve as ballast tanks and add structural rigidity while providing a protective second bottom above the keel if the outer hull is breached.
Question 5: When cargo is described as 'broken stowage,' this refers to:
- Damaged cargo that cannot be loaded
- The wasted space that cannot be utilized due to the shape or packaging of the cargo (Correct answer)
- Cargo stored in multiple holds
- Cargo requiring special lashing
Correct answer: The wasted space that cannot be utilized due to the shape or packaging of the cargo
Broken stowage is the unused void space in a hold that results from irregularly shaped cargo or packaging that prevents a perfect fit.
Question 6: What does the term 'freeboard' mean?
- The height of the mast above the waterline
- The distance from the waterline to the upper edge of the main deck (Correct answer)
- The space available for free cargo stowage
- The load capacity remaining after fuel is loaded
Correct answer: The distance from the waterline to the upper edge of the main deck
Freeboard is the vertical distance from the waterline to the freeboard deck (typically the main deck), indicating reserve buoyancy.
Question 7: Which cargo handling equipment is fixed to the ship's deck and uses a rotating drum to haul cargo?
- Derrick
- Winch (Correct answer)
- Davit
- Crane jib
Correct answer: Winch
A winch is a deck-mounted machine with a rotating drum that winds wire rope or cable to lift and lower cargo.
AB Ship Construction and Cargo 3
What is meant by 'GM' in ship stability terminology?