Merchant Marine Stability and Trim License Questions

The center of flotation of a vessel is __________. A. the center of volume of the immersed portion of the vessel B. the center of gravity of the water plane C. that point at which all the vertical downward forces of weight are considered to be concentrated D. that point at which all the vertical upward forces of buoyancy are considered to be concentrated

What is NOT a motion of the vessel? A. Pitch B. Roll C. Trim D. Yaw

A 7,000 ton displacement tankship carries two slack tanks of alcohol with a S.G. of 0.8. Each tank is 50 ft. long and 30 ft. wide. What is the reduction in GM due to free surface with the vessel floating in sea water, S.G. is 1.026? A. 0.36 ft   B.  0.46 ft   C.  0.72 ft   D. 0.82 ft

The percentage of the total surface area or volume of a flooded compartment that can be occupied by water caused by damage is known as __________. A. one compartment standard B. center of flotation C. permeability D. form gain

When water is used to fight a fire on board a ship, the effect of the weight of the water must be taken into account. How much sea water will increase the weight displacement by one ton? A. 64 cubic feet B. 35 cubic feet C. 100 gallons D. 500 liters

Forces within a vessel have caused a difference between the starboard and port drafts. This difference is called __________. A. list   B. heel   C. trim    D. flotation

The center of volume of the immersed portion of the hull is called the __________. A. center of buoyancy B. center of flotation C. center of gravity D. tipping center

Buoyancy is a measure of the ship's __________. A, ability to float B. deadweight C. freeboard D. midships strength

What is the reduction in metacentric height due to free surface when a tank 60 ft. wide and 60 ft. long is partially filled with saltwater? (The vessel's displacement is 10,000 tons.) A. 3.00 feet   B. 3.09 feet   C. 3.15 feet   D. 3.20 feet

Which statement about free surface is TRUE? A, A partially filled space with 40% surface permeability will have greater free surface effect than one with 60% surface permeability. B. Pocketing increases the loss of GM due to free surface effect. C. Cargo with a specific gravity of 1.05 has less free surface effect than a cargo with a specific gravity of 0.98. D. Pocketing occurs at small angles of inclination when a tank is 98% full.

Which is an indication of reserve buoyancy? A. Metacentric height B. Righting moment C. Rolling period D. Freeboard

Intact buoyancy is a term used to describe __________. A. the volume of all intact spaces above the waterline B. an intact space below the surface of a flooded area C. an intact space which can be flooded without causing a ship to sink D. the space at which all the vertical upward forces of buoyancy are considered to be concentrated

The ship's tanks most effective for trimming are the __________. A. deeps B. domestics C. peaks C. settlers

Which action will affect the trim of a vessel? A. Moving high weights lower B. Adding weight at the tipping center C. Moving a weight forward D. All of the above

A vessel carries three slack tanks of gasoline (SG .68). The vessel's displacement is 8,000 tons. Each tank is 50 ft. long and 20 ft. wide. What is the reduction in GM due to free surface with the vessel floating in sea water (SG 1.026)? A.  0.20 feet   B.  0.24 feet    C. 0.28 feet   D. 0.30 feet

Reserve buoyancy is __________. A. also called GM B. the void portion of the ship below the waterline which is enclosed and watertight C. affected by the number of transverse watertight bulkheads D. the watertight portion of a vessel above the waterline

A semisubmersible 300 feet long and an LCF of 0 (amidships) is in transit with hulls awash and an MT1" of 87.67 foot-tons. Work on the BOP (weight 263 long tons) requires that it be moved aft 12 feet. What is the resulting trim change? A. 1.5 feet B. 3.0 feet C. 6.0 feet D. 7.3 feet

A semisubmersible at a draft of 19 feet 9 inches arrives on location planning to deploy eight mooring lines. Each anchor weighs 15 long tons and each mooring line consists of 3,000 feet of 3-inch chain (89.6 lbs/ft). If no ballast corrections are made, what is the expected draft if the average TPI is 60? A. 17 feet 9 inches B. 18 feet 3 inches C. 18 feet 9 inches D. 21 feet 3 inches

The vertical distance between G and M of a MODU is used as a measure of __________. A. stability at all angles of inclination B. initial stability C. stability at angles less than the limit of positive stability D. stability at angles less than the downflooding angle

The purpose of the inclining experiment on a MODU is to determine the __________. A. lightweight and lightweight center of gravity location B. position of the center of buoyancy C. position of the metacenter D. maximum load line

Although KG for a MODU in lightweight is relatively high, the vessel is stiff because __________. A. KM is small B. KM is high C. BL is small D. KB is large

A semisubmersible at a draft of 19 feet 9 inches arrives on location planning to deploy eight mooring lines. Each anchor weighs 15 long tons and each mooring line consists of 3,000 feet of 3-inch chain (89.6 lbs/ft). If no ballast corrections are made, what is the expected draft if the average TPI is 60? A. 17 feet 9 inches B. 18 feet 3 inches C. 18 feet 9 inches D. 21 feet 3 inches

When a MODU is afloat in equilibrium, the horizontal component of mooring line tensions should equal __________. A. drilling forces B. weight forces C. buoyancy forces D. environmental forces

The vertical distance between G and M of a MODU is used as a measure of __________. (MODU = Mobile Offshore Drilling Unit. It behaves just like a ship!) A. stability at all angles of inclination B. initial stability C. stability at angles less than the limit of positive stability D. stability at angles less than the downflooding angle

The purpose of the inclining experiment on a MODU is to determine the __________. (MODU = Mobile Offshore Drilling Unit. It behaves just like a ship!) A. lightweight and lightweight center of gravity location B. position of the center of buoyancy C. position of the metacenter D. maximum load line

Although KG for a MODU in lightweight is relatively high, the vessel is stiff because __________. (MODU = Mobile Offshore Drilling Unit. It behaves no different than a ship!) A. M is small B. KM is high C. BL is small D. KB is large

The free surface effects of a partially-full tank in a floating MODU increase with the __________. (MODU = "Mobile Offshore Drilling Unit", Hint it floats so it behaves like a ship!) A. surface area of the fluid in the tank B. displacement volume of the MODU C. draft of the MODU D. height of the tank above the keel

A cargo of 30 tons is to be loaded on deck 30 feet from the ship's centerline. The ship's displacement including the 30 tons cargo will be 9,000 tons and the GM will be 5 feet. The list of the vessel after loading this cargo will be __________. A.  1.14°  B.  2.05°   C.  2.31°   D. 3.40°

While underway in a field move with the lower hulls awash, a semisubmersible has an allowable KG of 63.69 feet; KMT is 65.12 and KML is 64.92. The KGT is 56.13 and KGL is 55.89. What is the GML? A. 1.43 feet B. 7.56 feet C. 7.80 feet D. 9.03 feet

A vessel's heavy displacement is 24,500 tons with light displacement of 13,300 tons. Fully loaded it carries 300 tons of fuel and stores. What is the vessel's deadweight? A. 10,900 tons   B. 11,200 tons   C. 13,000 tons   D. 24,200 tons

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. 116 lengths of drill pipe. Each pipe weighs 0.644 long ton. The center of gravity is 1.11 feet above the main deck. II. 10 containers 8'L X 4'W X 3'H containing assorted pipe fittings and machine parts. Each container weighs 1-1/4 long tons, and the center of gravity of each box is 1.35 feet above the main deck. III. Two 90-fathom lengths of 3-inch diameter wire rope coiled on the main deck. Each foot of wire rope weighs 18.7 pounds. The center of gravity of the coil is 27 inches above the main deck. IV. 6 pallets of oak planking. Each pallet weighs 2-1/2 long tons with a center of gravity of 2.2 feet above the main deck. A. 2.23 feet   B. 1.93 feet  C. 1.82 feet  D. 1.38 feet

If your vessel has a list to port due to negative GM and off-center weight, the first corrective measure you should take is to __________. A. move port-side main deck cargo to the starboard side B. fill the starboard double-bottom C. pump water from the port double-bottom to the starboard double-bottom D. pump water from the port double-bottom over the side