Merchant Marine Stability and Trim License Questions

A tank 36 ft. by 36 ft. by 6 ft. is filled with water to a depth of 5 ft. If a bulkhead is placed in the center of the tank running fore-and-aft along the 36-foot axis, how will the value of the moment of inertia of the free surface be affected? A. The moment of inertia would remain unchanged. B. The moment of inertia would be 1/4 its original value. C. The moment of inertia would be 1/2 the original value. D. None of the above

A ship's forward draft is 22'-04" and its after draft is 24'-00". The draft amidships is 23'-04". This indicates a concentration of weight __________. A. at the bow B. in the lower holds C. amidships D. at the ends

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When a vessel is stationary and in a hogging condition,the main deck is under __________. A. compression stress B. tension stress C. shear stress D. racking stress

If a vessel is sagging, what kind of stress is placed on the sheer strake? A. Compression B. Tension C. Thrust D. Racking

Your vessel has a midships engine room and the cargo is concentrated in the end holds. The vessel is __________. A. sagging with tensile stress on main deck B. sagging with compressive stress on main deck C. hogging with tensile stress on main deck D. hogging with compressive stress on main deck

The first half about 4 minutes of the video shows how a Log Ship is loaded. The last 4 minutes shows how the vessel is forced to roll and has a view across the vessel's bridge so you can time the rolling period.

The two points that act together to trim a ship are the __________. A. LCF and LCB B. LCG and LCB C. Metacenter and LCG D. VCG and LCG

When a vessel's LCG is aft of her LCB, the vessel will __________. A. trim by the stern B. trim by the head C. be on an even keel D. be tender

The "trimming arm" of a vessel is the horizontal distance between the __________. A. LCB and LCF B. LCF and LCG C. LHA and LCG D. LCB and LCG

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Which would NOT provide extra buoyancy for a vessel with no sheer? A. Lighter draft B. Raised fo'c'sle head C. Raised poop D. Higher bulwark

The change in trim of a vessel may be found by __________. A. dividing the trim moments by MT1 B. subtracting the LCF from the LCB C. looking at the Hydrostatic Properties Table for the draft of the vessel D. dividing longitudinal moments by the displacement

A bulk freighter 680 ft. in length, 60 ft. beam, with a waterplane coefficient of 0.84, is floating in salt water at a draft of 21'. How many long tons would it take to increase the mean draft by 1"? A. 64.3 tons     B. 69.6 tons    C.  81.6 tons     D. 116 tons

Metacentric height is a measure of __________. A. initial stability only B. stability through all angles C. maximum righting arm D. All of the above

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Which statement is TRUE of a tender vessel? A. It has a large GM. B. Its period of roll is long. C. It has a very low center of gravity. D. It has a good transverse stability.

Which technique could be used to give a more comfortable roll to a stiff vessel? A. Concentrate weights on upper decks B. Add weight near the centerline of the lower hold C. Move weights lower in the ship D. Ballast the peak tanks

You are on a supply run to an offshore drilling rig. On board is the cargo listed. What is the height above the main deck of the center of gravity of the cargo? I. Drill casing - 50 lengths stowed in a block 8 feet high. Each pipe weighs 326 lbs. II. Crated valves - 10 crates stowed 2 high. Each crate is 36" L X 30" W X 15" H and weighs 1020 lbs. III. Dry stores - 14 containers stowed 2 high. Each container weighs 2 long tons and measures 6'L X 6'W X 6'H. IV. Anchors - 4. Each one on deck. The center of gravity of each anchor is 9" from the deck and each weighs 6120 lbs. A. 3.6 feet B. 4.2 feet C. 4.4 feet D. 4.9 feet

In order to minimize the effects of a tender vessel, when carrying a cargo of lumber, you should __________. A. maximize your deck load B. distribute lumber so that those stowing most compactly per unit of weight are in the upper holds C. place the heaviest woods in the lower holds D. keep the vessel's frame spaces free from lumber

You are on a supply run to an offshore drilling rig. On board is the cargo listed. What is the height above the main deck of the center of gravity of the cargo? I. 50 drums of cement. Each drum weighs 600 pounds and is stowed on end. Each drum measures 28 inches in diameter and is 32 inches high. II. Two reels of 1 inch diameter wire rope. Each reel contains 3000 linear feet of wire weighing 1.55 pounds per linear foot. The tare weight of each reel is 450 pounds. The reels are stowed on the flat and are 36 inches high. III. Twelve pallets of general supplies. Each pallet measures 8'L X 4'W X 3'H. The pallets are stowed singly and weigh 580 pounds each. IV. Twelve crates of machine parts and pipe fittings. Each weighs 880 pounds. Each crate measures 8'L X 3'W X 4'H and is stowed singly. A. 1.50 feet B.1.96 feet C. 2.21 feet D. 2.78 feet

A vertical shift of weight to a position above the vessel's center of gravity will __________. A. increase reserve buoyancy B. decrease the righting moments C. decrease KG D. increase KM

When a vessel has positive stability, the distance between the line of force through B and the line of force through G is called the __________. A. metacentric height B. righting arm C. righting moment D. metacentric radius

The purpose of the inclining experiment is to __________. A. determine the locationof the metacenter B. determine the lightweight center of gravity location C. verify the hydrostatic data D. verify data in the vessel's operating manual

Which is TRUE of a "stiff" vessel? A. It has a small GM. B. It pitches heavily. C. It has an unusually high center of gravity. D. Its period of roll is short.

The center of flotation of a vessel is the geometric center of the __________. A. underwater volume B. above water volume C. amidships section D. waterplane area

A vessel would be referred to as "tender" when the weight of the cargo is __________. A. evenly distributed vertically and the double bottoms are full B. concentrated low and the double bottoms are empty C. concentrated low and the double bottoms are full D. concentrated high and the double bottoms are empty

Addition of weight to a vessel will ALWAYS __________. A. reduce reserve buoyancy B. increase righting moments C. increase GM D. All of the above

A negative metacentric height __________. A. will always cause a vessel to capsize B. should always be immediately corrected C. always results from offcenter weights D. All of the above are correct

The effect of free surface on initial stability depends upon __________. A. the amount of liquid in the compartment B. the dimensions of the liquid surface and the vessel's displacement C. only the length of the compartment D. the vertical position of the liquid in the vessel

The point to which your vessel's center of gravity (G) may rise and still permit the vessel to have positive stability is called the __________. A. metacentric point B.  metacenter C.  metacentric radius D.  tipping center

Your vessel has a displacement of 10,000 tons. It is 350 feet (106.7 m) long and has a beam of 55 feet ( 16.8 m). You have timed it's full rolling period to be 15.0 seconds. What is your vessel's approximate GM? A. 1.18 feet (0.36 m) B. 1.83 feet (0.56 m) C. 2.60 feet (0.79 m) D. 3.36 feet (1.02 m)

Figure 7-13 on page 143 of STABILITY AND TRIM FOR THE SHIP'S OFFICER 4th Edition

On a vessel of 10,000 tons displacement, compute the reduction in metacentric height due to free surface in a hold having free water on the tank top. The hold is 40 feet (12.19 m) long and 50 feet ( 15.24 m)wide. The reduction in metacentric height is __________. A, 1.1 feet (0.335 m) B. 1.2 feet (0.366 m) C. 1.3 feet (0.393 m) D. 1.5 feet (0.457 m)

When a vessel has positive stability, the distance between the line of force through B and the line of force through G is called the __________. A. metacentric height B. righting arm C. righting moment D. metacentric radius

Which represents the righting arm? A. GM B. GZ C. BM D, KM

What represents the metacentric height? A. M B. GM C. BM D. GZ