PRC Naval Architect and Marine Engineer Licensure Examination (Philippines)

A ship with a displacement of 12,000 tonnes is floating in seawater (density = 1.025 t/m³). If the vessel enters fresh water (density = 1.000 t/m³), what happens to the displacement and the volume of displacement?

• AThe displacement remains the same, but the volume of displacement increases.
• BThe displacement increases, and the volume of displacement remains the same.
• CBoth displacement and volume of displacement remain the same.
• DBoth displacement and volume of displacement decrease.

A ship has a length between perpendiculars (LBP) of 140 m, a molded breadth of 22 m, and is floating at a draft of 7.5 m. If the molded displacement is 16,500 m³ in seawater, calculate the block coefficient (Cb) of the vessel.

• A0.714
• B0.685
• C0.752
• D0.620

Which of the following defines the midship section coefficient (Cm) of a vessel?

• AThe ratio of the molded midship section area to the product of the breadth and draft.
• BThe ratio of the volume of displacement to the volume of a prism of constant cross-sectio…
• CThe ratio of the waterplane area to the product of the length and breadth.
• DThe ratio of the centerline section area to the product of length and draft.

If a ship's waterplane area is 2,400 m², and the density of the surrounding seawater is 1.025 t/m³, calculate the Tons per Centimeter Immersion (TPC) of the vessel.

• A24.60 t/cm
• B24.00 t/cm
• C23.41 t/cm
• D25.21 t/cm

The prismatic coefficient (Cp) of a vessel is mathematically related to the block coefficient (Cb) and the midship section coefficient (Cm). What is this correct relationship?

• ACp = Cb / Cm
• BCp = Cb * Cm
• CCp = Cm / Cb
• DCp = Cb + Cm - 1

A vessel of constant rectangular cross-section has length L = 100 m, breadth B = 16 m, and floats at a draft T = 5 m. If the vessel is floating in fresh water, find the height of the center of buoyancy above the keel (KB).

• A2.50 m
• B3.33 m
• C1.67 m
• D5.00 m

The transverse metacentric radius (BM) of a vessel is calculated using the transverse second moment of area of the waterplane (I) and the volume of displacement (V). What is the correct formula?

• ABM = I / V
• BBM = V / I
• CBM = I * V
• DBM = (I * V) / 12

A ship has a KB of 3.8 m, a BM of 4.5 m, and a KG of 7.2 m. Calculate the metacentric height (GM) of this ship.

• A1.10 m
• B0.90 m
• C7.90 m
• D-1.10 m

Using the wall-sided formula for stability, calculate the righting lever (GZ) for a ship at an angle of heel (θ) of 15 degrees, given that GM = 0.8 m and BM = 3.0 m.

• A0.235 m
• B0.207 m
• C0.264 m
• D0.185 m

What is the primary cause of the 'angle of loll' in a merchant ship?

• AA negative initial metacentric height (GM) when the ship is in the upright position.
• BAn asymmetrical distribution of cargo on the port and starboard sides.
• CThe dynamic impact of beam winds and heavy rolling seas.
• DThe listing force generated by a high speed turning maneuver.

Moseley's formula is historically and theoretically significant in naval architecture because it is used to determine which of the following?

• ADynamical stability, representing the work done in heeling a ship to a given angle.
• BThe change of trim due to moving a weight longitudinally.
• CThe frictional resistance of a ship hull based on wetted surface area.
• DThe local bending stress in the deck plating under sagging conditions.

A ship has a displacement of 8,000 tonnes and a longitudinal metacentric height (GML) of 120 m. If the length of the ship is 100 m, calculate the Moment to Change Trim One Centimeter (MCTC).

• A96.0 t-m/cm
• B960.0 t-m/cm
• C9.60 t-m/cm
• D120.0 t-m/cm

A weight of 80 tonnes is moved longitudinally aft by a distance of 30 m on a vessel. If the ship's MCTC is 120 t-m/cm, calculate the total change of trim of the vessel.

• A20 cm aft
• B24 cm aft
• C18 cm aft
• D32 cm aft

A ship is floating at an initial draft of 6.2 m. A weight of 150 tonnes is added to the vessel at the Longitudinal Center of Flotation (LCF). If the TPC is 25 t/cm, what is the new draft?

• A6.26 m
• B6.20 m
• C6.32 m
• D6.14 m

A ship displacing 10,000 tonnes has a vertical center of gravity (KG) of 8.0 m. A cargo weight of 500 tonnes is loaded at a height of 12.0 m above the keel. Find the new KG of the vessel.

• A8.19 m
• B8.25 m
• C8.10 m
• D8.05 m

How does the Free Surface Effect (FSE) of a partially filled tank affect the metacentric height (GM) of a vessel?

• AIt decreases the effective GM by raising the virtual center of gravity (G) of the vessel.
• BIt increases the effective GM by lowering the virtual center of gravity (G).
• CIt does not change the GM, but it shifts the metacenter (M) downward.
• DIt decreases the GM only when the ship is at large angles of heel exceeding 30 degrees.

A box-shaped vessel (L = 60 m, B = 10 m, T = 3 m) is bilged in a central empty compartment that is 6 m long and spans the full breadth. Using the lost buoyancy method, calculate the new draft of the vessel.

• A3.33 m
• B3.50 m
• C3.15 m
• D3.60 m

In damaged stability, what is the primary operational difference between the 'lost buoyancy method' and the 'added weight method'?

• ALost buoyancy keeps displacement constant and changes the hull geometry; added weight inc…
• BLost buoyancy increases displacement; added weight decreases displacement.
• CLost buoyancy is only valid for small damage; added weight is only valid for large damage.
• DLost buoyancy assumes water does not enter the ship; added weight assumes water fills the…

According to the ITTC-1957 correlation line, what parameters primarily determine the frictional resistance coefficient (Cf) of a ship?

• AReynolds number (Re) only.
• BFroude number (Fn) only.
• CFroude number (Fn) and block coefficient (Cb).
• DReynolds number (Re) and wave-making coefficient (Cw).

A ship has a length of 144 m and is operating at a speed of 18 knots (approximately 9.26 m/s). Calculate the Froude number (Fn) of the vessel.

• A0.246
• B0.312
• C0.185
• D0.288

What is the physical meaning of the 'form factor' (1 + k) used in modern ship resistance prediction?

• AIt represents the three-dimensional viscous pressure drag (form drag) as a fraction of th…
• BIt is a correction factor for the wave-making resistance based on bulbous bow geometry.
• CIt represents the mechanical efficiency of the shafting system and reduction gear.
• DIt is the ratio of wetted surface area to the block coefficient of the ship.

A ship has a total resistance of 600 kN at a service speed of 16 knots (8.23 m/s). Calculate the Effective Horsepower (EHP) of the vessel in kilowatts.

• A4,938 kW
• B7,290 kW
• C3,600 kW
• D5,550 kW

The pitch of a propeller is 6.0 m. The engine turns the propeller at 120 RPM, and the ship's speed through the water is 11.0 m/s. Calculate the apparent slip ratio.

• A0.083
• B0.120
• C0.052
• D0.154

What is the wake fraction (w) if a vessel's speed through the water is 15 knots, and the speed of advance (Va) of the water at the propeller disk is 12 knots?

• A0.20
• B0.25
• C0.15
• D0.30

The thrust deduction fraction (t) represents the loss of thrust due to the interaction between the propeller and the hull. If the thrust generated by the propeller is T, and the ship's tow-rope resistance is R, what is the correct relationship?

• AR = T * (1 - t)
• BR = T * (1 + t)
• CT = R * (1 - t)
• DR = T / (1 - t)

Which of the following describes the condition under which cavitation is most likely to begin on a marine propeller blade?

• AWhen the local pressure on the suction side drops below the vapor pressure of the water.
• BWhen the slip of the propeller is negative during stopping maneuvers.
• CWhen the local water velocity on the pressure side is reduced to zero.
• DWhen the blade thickness exceeds the hub diameter ratio.

When a ship girder experiences 'hogging' in a seaway, what is the nature of the primary longitudinal stresses in the deck and the keel?

• AThe deck is in tension, and the keel is in compression.
• BThe deck is in compression, and the keel is in tension.
• CBoth the deck and the keel are in tension.
• DBoth the deck and the keel are in compression.

A ship's hull girder has a vertical moment of inertia (I) of 4.5 x 10^6 m²-cm² (or 450 m^4). If the distance from the neutral axis to the strength deck is 8.0 m, and the maximum bending moment amidships is 360,000 kN-m, calculate the maximum tensile stress on the strength deck.

• A6,400 kN/m²
• B8,000 kN/m²
• C5,500 kN/m²
• D7,200 kN/m²

Why do modern open-top container ships require heavy box-shaped torsional girders along the deck edge (torsional boxes)?

• ATo compensate for the lack of a continuous strength deck and resist torsional twisting fo…
• BTo serve as ballast tanks to lower the ship's center of gravity.
• CTo protect the cargo holds from sea spray and transverse wave entry.
• DTo support the weight of the heavy gantry cranes installed on deck.

What does a 'KN curve' (cross curve of stability) represent in ship stability analysis?

• AThe righting lever (GZ) calculated about an assumed coordinate center (keel K) for variou…
• BThe vertical distance from the keel to the transverse metacenter as a function of draft.
• CThe thrust generated by the propeller as a function of ship speed and RPM.
• DThe change of buoyancy longitudinal center (LCB) with respect to heel angle.

In marine engineering, large slow-speed main propulsion engines (typically operating below 120 RPM) are almost exclusively of which type?

• ATwo-stroke, crosshead diesel engines.
• BFour-stroke, trunk-piston diesel engines.
• CTwo-stroke, trunk-piston diesel engines.
• DFour-stroke, crosshead diesel engines.

Which scavenging method is widely considered the most efficient for modern two-stroke crosshead marine diesel engines, utilizing exhaust valves in the cylinder cover?

• AUniflow scavenging.
• BLoop scavenging.
• CCross scavenging.
• DReverse-loop scavenging.

A 6-cylinder, single-acting, two-stroke marine diesel engine has a cylinder bore of 0.6 m, a stroke of 2.0 m, and operates at 100 RPM. If the indicated mean effective pressure (IMEP) is 15 bar (1,500 kPa), calculate the indicated power of the engine.

• A8,482 kW
• B4,241 kW
• C16,964 kW
• D10,603 kW

An auxiliary engine produces 1,200 kW of power while consuming 240 kg of fuel oil per hour. Calculate the Specific Fuel Oil Consumption (SFOC) of this engine.

• A200 g/kW-h
• B180 g/kW-h
• C220 g/kW-h
• D250 g/kW-h

What is the primary difference in exhaust gas routing between impulse and constant-pressure turbocharging systems in marine engines?

• AImpulse uses narrow pipes to preserve kinetic energy from individual cylinder pulses; con…
• BImpulse maintains a constant pressure at the turbine nozzle; constant-pressure routes exh…
• CImpulse routes exhaust through the auxiliary boiler; constant-pressure bypasses the turbo…
• DImpulse is only used on two-stroke engines; constant-pressure is only used on four-stroke…

What is the operational function of an exhaust gas economizer (waste heat recovery boiler) on a motor ship?

• ATo generate steam using the heat from the main engine exhaust gases when at sea.
• BTo reheat the scavenge air before it enters the cylinders to improve combustion.
• CTo condense exhaust steam from the auxiliary turbine generators back into fresh water.
• DTo remove soot particles from the exhaust stream using water spray scrubbing.

How does regenerative feed heating improve the thermodynamic efficiency of a marine steam turbine plant?

• ABy using steam bled from intermediate turbine stages to preheat the boiler feed water.
• BBy passing the flue gases through a rotary air preheater before they exit the stack.
• CBy returning high-pressure exhaust steam back to the boiler superheater.
• DBy spray-cooling the turbine blades to reduce thermal stresses during rapid maneuvering.

What is the primary function of the 'hunting gear' in a hydraulic steering gear system?

• ATo return the control valve of the hydraulic pump to the neutral position when the rudder…
• BTo prevent the steering gear from turning beyond the maximum mechanical limit of 35 degre…
• CTo automatically steer the vessel along a set GPS path when on autopilot.
• DTo equalize the hydraulic pressure between the port and starboard cylinders during heavy…

Under SOLAS regulations, what is the maximum time allowed for the main steering gear to turn the rudder from 35 degrees on one side to 30 degrees on the other side at deepest draft and maximum speed?

• A28 seconds
• B45 seconds
• C15 seconds
• D60 seconds

MARPOL Annex I mandates that oily bilge water discharged into the sea from ships of 400 gross tonnage and above must pass through an Oily Water Separator (OWS) and have an oil content of not more than what limit?

• A15 ppm
• B5 ppm
• C50 ppm
• D100 ppm

In a biological marine sewage treatment plant, what is the purpose of adding air to the aeration chamber?

• ATo supply oxygen to aerobic bacteria that digest and decompose organic waste.
• BTo oxidize toxic hydrogen sulfide gas into harmless water vapor.
• CTo increase the pressure inside the tank to push the treated sewage overboard.
• DTo evaporate the liquid portion of the waste to reduce sludge volume.

In a shipboard vapor-compression refrigeration cycle, what is the thermodynamic state of the refrigerant as it leaves the compressor and enters the condenser?

• ASuperheated, high-pressure vapor.
• BSaturated, low-pressure liquid.
• CSubcooled, high-pressure liquid.
• DWet, low-pressure vapor mixture.

What is cavitation in a centrifugal pump, and how can Net Positive Suction Head (NPSH) prevent it?

• AIt is the formation of vapor bubbles when the local pressure drops below vapor pressure;…
• BIt is the erosion caused by solid particles in the suction line; to prevent it, the pump…
• CIt is the air binding of the impeller; to prevent it, the suction valve must be throttled…
• DIt is the axial thrust on the pump shaft; to prevent it, double-entry impellers must be u…

Why are non-return valves (screw-down non-return valves) mandatory in the bilge suction lines of a ship's bilge system?

• ATo prevent water from the sea or ballast systems from accidentally flooding the dry bilge…
• BTo allow the bilge pump to run in reverse to pump clean water into the bilge wells for cl…
• CTo prevent the bilge pump from running dry by trapping priming water in the lines.
• DTo allow the bilge system to double as a fire-main supply line during emergencies.

What three conditions must be synchronized before closing the circuit breaker to connect an incoming generator in parallel with an online generator?

• AVoltage, frequency, and phase relationship.
• BVoltage, current, and power factor.
• CSpeed, cylinder exhaust temperature, and excitation current.
• DFrequency, total load, and power factor.

What is the primary function of the Michell-type thrust bearing in a ship's propulsion shafting?

• ATo transmit the axial thrust generated by the propeller to the ship's hull structure.
• BTo support the radial weight of the heavy tailshaft and prevent shaft sagging.
• CTo absorb the torsional vibrations generated by the main engine cylinders.
• DTo seal the stern tube and prevent seawater from leaking into the engine room.