OSV – Assistant Engineer, Revision & Practice Exams

When required to work in an area where explosive gases may accumulate, you should use hand tools which are __________.

1. approved by the Coast Guard
2. high carbon steel
3. non-ferrous ✓
4. fixed with a ferrous cover

When fighting a shipboard fire, crew members securing doorways, hatches, and applying cooling water to adjacent decks and bulkheads, while monitoring the spread of heat and smoke, are setting a _________.

1. fire boundary ✓
2. buffer zone
3. cooling zone
4. safety perimeter

Which of the following conditions is true concerning flammable liquid vapors with a concentration above the upper explosive limit?

1. The mixture is too lean to burn.
2. Conditions are perfect for combustion.
3. The vapor is about to explode.
4. The mixture is too rich to burn. ✓

In accordance with 33 CFR Subchapter O (Pollution), the Oil Record Book for all U.S. ships ________.

1. Is the property of the U.S. government ✓
2. Is required to have entries recorded within 48 hours of completion of the particular operation
3. Should not be used to record the accidental discharge of oil or oily mixtures
4. Is to be kept in the personal possession of the master

Both the direction of flow and fluid flow rate of a variable displacement radial piston pump are determined by the relative positions of the __________.

1. floating ring and pump shaft
2. floating ring and cylinder body ✓
3. pump shaft and horizontal ports
4. pump shaft and central valve

What is the primary purpose of the lead-lag arrangement of the two potable water pumps supporting a typical potable water system?

1. Enabling the lead pump to pump against a shut-off head during periods of relatively low demand and the lag pump to recirculate when the demand is high.
2. Enabling both potable water pumps to cycle on and off together in response to system demand changes.
3. Enabling the lead pump to cycle on and off during periods of relatively low demand and the lag pump to assist the lead pump only when the demand is high. ✓
4. Enabling the lag pump to cycle on and off during periods of relatively low demand and the lead pump to assist the lag pump only when the demand is high.

When configuring a digital multimeter as an ohmmeter, what will MOST likely be displayed on the screen when the test leads are shorted together?

1. A reading of "OL" ohms will be displayed.
2. A reading of residual test lead and internal resistance will be displayed (typically .2 to .5 ohms).
3. A reading of 0 ohms will be displayed.
4. B or C could be correct depending upon the digital multimeter. ✓

The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts. How is this done?

1. extinguishing the arc by means of an arc chute ✓
2. an inverse timed thermal trip for short circuit currents
3. designing the contacts to open slowly
4. instantaneous magnetic trip for overload currents

How are operational amplifiers, used primarily in analog circuits, characterized?

1. high input impedance, high gain and low output impedance ✓
2. high input impedance, high gain and high output impedance
3. low input impedance, high gain and low output impedance
4. low input impedance, low gain and high output impedance

Referring to figure "4" of the illustration, what type of logic gate is symbolized? Illustration EL-0035

1. AND gate
2. NOR gate
3. NAND gate ✓
4. XOR gate

An electric propulsion drive system in which the propulsion generator supplies power to both the propulsion motor and ship service loads is referred to as what type of system?

1. a composite system
2. a dedicated system
3. a multi-purpose system
4. an integrated system ✓

A 'centerline' depicted in a drawing or blueprint is represented by which of the figures shown in the illustration? Illustration GS-0031

1. A
2. E ✓
3. C
4. D

Which fire extinguisher is most prone to freezing when stowed in low temperatures?

1. Foam ✓
2. Carbon dioxide
3. Halon 1211
4. Dry chemical

With no environmental forces acting on the vessel, the center of gravity of an inclined vessel is vertically aligned with the __________.

1. Original vertical centerline
2. Center of buoyancy ✓
3. Center of flotation
4. Longitudinal centerline

Contact with any energized electrical system conductor is potentially hazardous and precautions should be taken to prevent exposure. With all other factors considered equal (such as voltage, conducting path through the body and the duration of contact), contact with an energized electrical system conductor of which system type would produce the most damaging effect?

1. DC systems
2. 60 Hz AC systems ✓
3. 10 kHz AC systems
4. All the above systems would be equally as damaging

In heavy seas the helmsman should steer the survival craft __________.

1. into the seas ✓
2. broadside to the seas
3. in the same direction as the seas
4. in a series of figure-eights

Which of the following statements represents the proper criteria to decide when to drain a filter/moisture separator as used in a ship's service air system hose station?

1. The bowl should be drained whenever moisture droplets appear in the bowl.
2. The bowl should be drained before the moisture level reaches the lower baffle. ✓
3. The bowl should be drained after the bowl completely fills with moisture.
4. The bowl should be drained daily with no need to check the moisture level.

Which pair of safety disconnect switches shown in the illustration represents the exterior and interior views of a double-throw switch? Illustration EL-0176

1. A and B
2. B and D ✓
3. C and D
4. A and C

If a life raft should capsize, __________.

1. climb onto the bottom
2. swim away from the raft
3. right the raft using the righting straps ✓
4. inflate the righting bag

Which of the following statements is true concerning the gauge labeled "A" of the illustrated gauge manifold set? Illustration RA-0001

1. The gauge labeled "A" is a compound gauge and is usually color-coded red.
2. The gauge labeled "A" is a standard pressure gauge and is usually color-coded blue.
3. The gauge labeled "A" is a standard pressure gauge and is usually color-coded red.
4. The gauge labeled "A" is a compound gauge and is usually color-coded blue. ✓

From the information given in the illustration, what would be the maximum output amperage available from the emergency generator if it operated with a power factor of 0.9? Illustration EL-0106

1. 541 amps
2. 669 amps ✓
3. 937 amps
4. 1156 amps

For diesel engines, such as those used for main propulsion and auxiliary power on offshore supply vessels, while running at speed, how is the ignition of fuel within the cylinder achieved?

1. Ignition is achieved by the heat of compression created by compressing intake/charge air within the cylinder into a relatively small volume. ✓
2. Ignition is achieved by a high voltage electric spark induced across the gap of a specially designed spark plug.
3. Ignition is achieved by the heat of compression created by compressing the air/fuel mixture within the cylinder into a relatively small volume.
4. Ignition is achieved by intense heat by passing electric current through the element of a specially designed glow plug.

You are assigned to a platform supply vessel fitted with main propulsion diesel engines of the type shown in the illustration. If the engine's crankshaft is turning at 900 rpm, what will be the rotational speed of the two camshafts? Illustration MO-0224

1. 450 rpm
2. 900 rpm ✓
3. 1800 rpm
4. Not enough information is given to determine camshaft rpm.

You are assigned to an offshore supply vessel fitted with main propulsion diesel engines of the type shown in the illustration. If the engine's crankshaft is turning at 720 rpm, what will be the rotational speed of the two camshafts? Illustration MO-0005

1. 360 rpm ✓
2. 720 rpm
3. 1440 rpm
4. Not enough information is given to determine camshaft rpm

The multi-purpose offshore supply vessel to which you are assigned is fitted with main propulsion diesel engines of the type shown in the illustration. In terms of valve operating gear, cylinder liner type, and connecting rod type, what statement is true? Illustration MO-0192

1. This is a pushrod operated overhead valve engine, with wet cylinder liners and conventional connecting rods. ✓
2. This is a pushrod operated overhead valve engine, with jacketed cylinder liners and articulated connecting rods.
3. This is an overhead cam engine, with wet cylinder liners and conventional connecting rods.
4. This is an overhead cam engine, with jacketed cylinder liners and marine-type connecting rods.

When starting a deck winch drive engine in preparation for cargo handling operations, what parameter must be checked FIRST upon start-up to avoid immediate engine damage?

1. Fuel oil supply header pressure
2. Cylinder jacket water pump discharge pressure
3. Engine lubricating oil supply header pressure ✓
4. Deck winch gear oil pump discharge pressure

On diesel engines used on a multi-purpose supply vessel, which type of injection system is most likely to use sophisticated electronic controls for timing and metering?

1. Distributor type pump
2. Unit injector type pump ✓
3. Rotary plunger type pump
4. In-line multi-plunger pump

The offshore supply vessel to which you are assigned has main engines fitted with intake and exhaust systems as shown in the illustration. What statement is true concerning the turbocharger charge air discharge arrangements? Illustration MO-0177

1. The left side turbocharger discharges charge air to the right cylinder bank, and the right side turbocharger discharges charge air to the left cylinder bank. ✓
2. It is not possible to determine the turbocharger charge air discharge arrangements in this particular drawing.
3. The left side turbocharger discharges charge air to both cylinder banks, and the right side turbocharger discharges charge air to both cylinder banks.
4. The left side turbocharger discharges charge air to the left cylinder bank, and the right side turbocharger discharges charge air to the right cylinder bank.

The oil platform construction support vessel to which you are assigned has main diesel engines fitted with intake and exhaust systems as shown in the illustration. If the main engine is running under a heavy load at maximum rpm, which pressure would ordinarily be negative? Illustration MO-0180

1. Air intake ✓
2. Exhaust receiver
3. Air box
4. Exhaust discharge to stack

The diesel engines on your general-purpose supply vessel are all protected with dry-type air filters. The air filters should be inspected and replaced in accordance with manufacturer instructions. What is the generally accepted criteria that would dictate when filter replacement becomes necessary?

1. The air filter element should be replaced when the pressure drop across the element increases above the specified maximum. ✓
2. The air filter element should be replaced when the pressure rise across the element decreases below the specified minimum.
3. The air filter element should be replaced when the pressure drop across the element decreases below the specified minimum.
4. The air filter element should be replaced when the pressure rise across the element increases above the specified maximum.

The anchor handling supply vessel to which you are assigned has diesel generator engines fitted with intake and exhaust systems as shown in the illustration. What type of turbo-charging configuration is used? Illustration MO-0176

1. Boost-controlled turbocharging
2. Constant pressure turbocharging
3. 2-stage turbocharging
4. Pulse turbocharging ✓

The freshwater cooling systems serving the main engines of the platform supply vessel to which you are assigned are arranged as shown in the illustration. What statement best describes the arrangement of the freshwater keel cooler shown in the system diagram? Illustration MO-0138

1. The keel cooler is mounted on the inside of the hull below the water line.
2. The keel cooler is mounted on the outside of the hull below the water line. ✓
3. The keel cooler is mounted on the outside of the hull above the water line.
4. The keel cooler is mounted on the inside of the hull above the water line.

The auxiliary engines on the offshore supply vessel to which you are assigned are fitted with Roots-blowers as shown in the illustration. What statement is true concerning the timing gears as shown in figure "A"? Illustration MO-0135

1. The timing gears are helically cut and ensure that the blower is properly timed to the engine's crankshaft.
2. The timing gears are helically cut and ensure that the blower rotor lobes are properly spaced apart with a close tolerance. ✓
3. The timing gears are straight cut and ensure that the blower rotor lobes are properly spaced apart with a close tolerance.
4. The timing gears are straight cut and ensure that the blower is properly timed to the engine's crankshaft.

The two-stroke cycle main propulsion engines on the supply boat to which you are assigned are fitted with Roots-type blowers for scavenging purposes. Upon inspection of the air boxes, what condition would indicate a need to replace the Roots-type blower immediately?

1. Water accumulations
2. Oil accumulations
3. Aluminum dust residue ✓
4. Iron dust residue

The lubricating oil system supporting the main propulsion reduction gear on your offshore supply vessel is fitted with a lube oil strainer as shown in the illustration. How often should the handle "A" be rotated for cleaning purposes? Illustration MO-0057

1. Once per watch while underway ✓
2. Once per month
3. Once every six months
4. Once per year

The anchor handling vessel to which you are assigned has a pneumatic propulsion control system as shown in the illustration. Which control valve is responsible for by-passing the inflation delay orifice to insure rapid and positive reversals and to protect the clutches from excessive slip? Illustration MO-0167

1. H5 boost relay air valve ✓
2. C2 speed-slip relay valve
3. H5 inflation air relay valve
4. H5 governor limit relay air valve

The steam generating plant on your oil spill response vessel is of the forced-circulation type. Which figure of the illustration represents a steam generator or boiler of this type? Illustration MO-0197

1. 1
2. 2
3. 3 ✓
4. 4

The auxiliary oil-fired water-tube steam boiler on your anchor-handling supply vessel is equipped with a water column similar to that shown in the illustration. If the gauge glass becomes disabled or there is uncertainty associated with the gauge glass reading, the tricocks can be used to determine the boiler water level. What statement best describes the challenge associated with trying to differentiate between steam and water? Illustration MO-0093

1. On a tricock situated below the water level, when opened some of the escaping water will flash to steam. ✓
2. On a tricock situated below the water level, when opened all of the escaping water will flash to steam.
3. On a tricock situated above the water level, when opened all of the escaping steam will condense to water.
4. On a tricock situated above the water level, when opened some of the escaping steam will condense to water.

Diesel engine closed, recirculating cooling water systems are particularly prone to cavitation corrosion/erosion. Which of the listed cooling system/engine components has surfaces in contact with the coolant that are most susceptible to this type of corrosion and erosion?

1. Cylinder head cooling water passages
2. Cylinder cooling water jackets
3. Wet-type cylinder liners ✓
4. Engine exhaust cooling water jackets

The air charge leaving an intercooler or after cooler of an air compressor can be expected to be which of the following?

1. Superheated.
2. At or below the dew point. ✓
3. Supercooled.
4. All of the above.

In a twin-tower desiccant type air dryer using silica gel as an adsorbing agent, what is the procedure for rejuvenating the tower presently on service when the desiccant becomes saturated with moisture?

1. The tower on service is refrigerated and it remains on service while cooling.
2. The towers are shifted, and heat is applied to the off-going tower. ✓
3. Heat is applied to the tower on service and it remains on service while heating.
4. The towers are shifted, and the off-going tower is refrigerated.

With regard to the relative flow patterns through the tubes and the shell of shell-and-tube heat exchangers, what statement is true?

1. In a parallel-flow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions.
2. In a counterflow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions. ✓
3. In a cross-flow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions.
4. In a counterflow heat exchanger, the flow through the tubes and the flow through the shell are in the same direction.

With regard to the flow patterns associated with plate type heat exchangers, which flow pattern is able to achieve counterflow on opposite sides of each heat exchange plate?

1. The flow pattern where one fluid makes a single pass and the other makes multiple passes through the heat exchanger.
2. The flow pattern where each fluid makes a single pass through the heat exchanger. ✓
3. The flow pattern where each fluid makes multiple passes through the heat exchanger.
4. It is not possible for each heat exchanger plate to achieve counterflow on opposite sides.

A three inch overboard discharge line, located six feet below the waterline, has ruptured and separated from the hull. What would be the minimum number of strokes per minute required from a 10" x 8" x 12" duplex double acting steam operated reciprocating bilge pump, operating at 96% efficiency, to keep the bilge water level from continuing to rise? (231 cu in = 1 gal) Illustration SF-0034

1. 45 strokes per minute
2. 56 strokes per minute
3. 87 strokes per minute ✓
4. 98 strokes per minute

Which of the following statements is true concerning the Halon 1301 fire extinguishing agent?

1. Halon extinguishes the fire by a chain breaking reaction. ✓
2. The agent is highly toxic as stored in pressurized cylinders.
3. The agent is less effective than carbon dioxide.
4. The agent cannot be used on electrical fires because it leaves a residue.

Low velocity water fog is used in firefighting as a __________.

1. barrier against radiant heat
2. smothering agent
3. cooling agent
4. all of the above ✓

While in a foreign port, burning and welding repairs are to be carried out on a section of heating coil located in a tank having last contained a grade "D" product. Which of the following procedures should be followed when a certified marine chemist is not available?

1. It is solely the chief engineer's responsibility to ensure all safety precautions are observed, and all entries are to be made in the engine room log.
2. Repairs should proceed as scheduled since a chemist's certificate is not required for that type of work.
3. The repair work cannot be done at this time due to the lack of the chemist's certificate.
4. Prior to any hot-work, an inspection must be made by the senior officer present, and an entry made in the official logbook. ✓

Static water pressure on the hull of a ship is greatest at the __________.

1. boot topping
2. stern
3. bow
4. keel ✓

Reserve buoyancy is the __________.

1. volume of intact space above the waterline ✓
2. unoccupied space below the waterline
3. difference between buoyancy in salt and fresh waters
4. excess of the buoyant force over gravitational force

For the purpose of calculating line current, which of the following procedures should be used to determine the total line current of a three-phase, delta wound, AC generator?

1. Divide the total amperage in all phases by the square root of three.
2. Multiply the amperage in one phase by three.
3. Multiply the amperage in one phase by the square root of three. ✓
4. Divide the total amperage in all phases by three.

What is the most practical method of controlling the RPM of a multi-speed AC motor operating at a constant frequency?

1. change the input voltage
2. change the power factor
3. change the number of operating poles ✓
4. change the number of brushes

The individual 12-volt lead-acid batteries, when connected as shown in the illustration, as a battery bank would produce how many volts? Illustration EL-0070

1. 12 volts ✓
2. 24 volts
3. 36 volts
4. 48 volts

What is the primary means by which an electrical maintenance worker is protected from electrical hazards while performing work on an electrical circuit?

1. shutting down the necessary equipment
2. using the appropriate personal protective equipment
3. performing a lock-out/tag-out procedure ✓
4. posting of safety warning signs

Referring to the illustration, what is the position of the three circuit breakers labeled in figure A, B, and C respectively? Illustration EL-0033

1. Circuit breaker in figure A is in the ON position. Circuit breaker in figure B is in the TRIPPED position. Circuit breaker in figure C is in the OFF position.
2. Circuit breaker in figure A is in the ON position. Circuit breaker in figure B is in the OFF position. Circuit breaker in figure C is in the TRIPPED position.
3. Circuit breaker in figure A is in the OFF position. Circuit breaker in figure B is in the ON position. Circuit breaker in figure C is in the TRIPPED position. ✓
4. Circuit breaker in figure A is in the OFF position. Circuit breaker in figure B is in the TRIPPED position. Circuit breaker in figure C is in the ON position.

When a transformer is used to step down voltage, what statement is true?

1. The low voltage winding is not insulated.
2. The low voltage winding is the primary coil.
3. The low voltage winding is part of the core.
4. The low voltage winding is the secondary coil. ✓

The propulsion motor most often utilized in an AC drive system operating in the moderate to high power range is of what type?

1. wound rotor induction type
2. split-phase induction type
3. squirrel-cage induction type
4. synchronous type with wound field ✓

Occasionally a synchronous motor is configured without an external shaft to drive a load. In this case, the sole purpose of the synchronous motor is improving overall power factor of an electrical distribution system. What is the name of the synchronous motor so constructed?

1. Motor-generator
2. Synchronous converter
3. Synchronous condenser ✓
4. Synchronous compensator

Referring to the containership one-line distribution diagram shown in the illustration, what statement is true concerning the battery charger? Illustration EL-0014

1. The battery charger gets its AC power from the 120 VAC section of the main switchboard and is capable of providing DC charging current to only one battery bank at a given time.
2. The battery charger gets its AC power from the 120 VAC section of the emergency switchboard and is capable of providing DC charging current to only one battery bank at a given time. ✓
3. The battery charger gets its AC power from the 120 VAC section of the emergency switchboard and is capable of providing DC charging current to both battery banks simultaneously.
4. The battery charger gets its AC power from the 120 VAC section of the main switchboard and is capable of providing DC charging current to both battery banks simultaneously.