National Maritime Center

Transcription

1 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU (Sample Examination) 8/31/2017 Page 1 of 26

2 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: 14 Choose the best answer to the following Multiple Choice Questions. 1. When the oily-water separator, shown in the illustration, is in operation and processing clear bilge water, what should be the internal water level? Illustration GS-0153 o (A) The water level in the tank should be slightly above the upper coalescer bed "9". o (B) The water level should be located in the lower section of the tank as controlled by flow control valve "14". (C) The water level should be located in the upper section of the tank. o (D) No water level is maintained in the tank. If choice C is selected set score to In accordance with 33 CFR Subchapter O (Pollution), which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flushwater at ambient air pressure and temperature? o (A) Type I o (B) Type II (C) Type III o (D) Type IV If choice C is selected set score to Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? (A) when charging as a liquid it should be to the high side only o (B) when charging as a liquid it should be to the low side only o (C) when charging as a vapor it should be directly to the receiver only o (D) when charging as a liquid it may be to the low or high side 4. Three 12 volt, lead-acid, batteries connected in series will develop how many volts? o (A) 12 volts o (B) 24 volts (C) 36 volts o (D) 48 volts If choice C is selected set score to 1. 8/31/2017 Page 2 of 26

3 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: Referring to the illustrated motor ship fresh water cooling system drawing, which cooling system has cooling water passing through passages within components that are continuously undergoing motion? Illustration MP-CW-06 o (A) The main engine jacket water cooling system. o (B) The SSDG cooling water systems. (C) The main engine piston cooling water system. o (D) The main engine injector cooling water system. If choice C is selected set score to Which of the listed valve types is typically used for the intermediate and high pressure stages of a reciprocating air compressor? (A) Ring-plate o (B) Strip-type o (C) Sliding o (D) Rotary 7. What statement is true concerning the term "isochronous" as it applies to prime mover speed control governors? o (A) Isochronous governors are able to maintain constant prime mover load regardless of speed by employing temporary speed droop. o (B) Isochronous governors are able to maintain constant prime mover load regardless of speed by employing permanent speed droop. (C) Isochronous governors are able to maintain constant prime mover speed regardless of load by employing temporary speed droop. o (D) Isochronous governors are able to maintain constant prime mover speed regardless of load by employing permanent speed droop. If choice C is selected set score to In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor? o (A) compressor suction pressure o (B) temperature in the box (C) temperature of the evaporator coil outlet o (D) heat transferred from the saturated liquid in the evaporator If choice C is selected set score to 1. 8/31/2017 Page 3 of 26

4 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: In which lubrication application is a detergent type oil most likely to be used? o (A) Air compressor lubricating oil. (B) Trunk type diesel engine lubricating oil. o (C) Steam turbine lubricating oil. o (D) Crosshead diesel engine bearing lubricating oil. If choice B is selected set score to Which of the conditions listed does the blueprint symbol shown in the illustration represent? Illustration GS-0028 (A) All surfaces are to be machine finished. o (B) A groove must be machined at the points designated. o (C) The thread form to be machined on the bolt. o (D) The surface should be finished with a welded overlay. 11. The low-pressure cut-out switch settings vary with the refrigerant used and the temperature application. If the low-pressure cut-out switch for a particular application is set with a cut-in pressure of 5 psig, what would be the cut-out pressure if the differential is 7.5 psig? (A) 5" Hg o (B) 0 psig o (C) 2.5 psig o (D) 12.5 psig 12. As shown in figure "B" of the illustrated self-contained recovery unit connection diagrams, what is the recovery method supported by the connection scheme? Illustration GS-RA-33 (A) direct vapor recovery o (B) direct liquid recovery o (C) liquid recovery/push-pull o (D) vapor recovery/push-pull 13. Which of the following rotational shaft speed sensors produces a digital signal? (A) Optical tachometer o (B) Brush-type DC tachometer o (C) Brushless DC tachometer o (D) AC tachometer 8/31/2017 Page 4 of 26

5 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: To measure the circumference of a piece of pipe, you should use a. o (A) folding rule o (B) hook rule (C) flexible steel rule o (D) machinist's steel rule If choice C is selected set score to With regard to the number of passes through the tubes of shell-and-tube heat exchangers, what statement is true? o (A) In two-pass and four-pass heat exchangers, the inlet and outlet tube-side fluid connections are at opposite ends. o (B) In single-pass and two-pass heat exchangers, the inlet and outlet tube-side fluid connections are at opposite ends. o (C) In single-pass and two-pass heat exchangers, the inlet and outlet tube-side fluid connections are at the same end. (D) In two-pass and four-pass heat exchangers, the inlet and outlet tube-side fluid connections are at the same end. If choice D is selected set score to Which of the methods listed below is used to provide the rotational torque to cause an AC generator to turn? o (A) Residual magnetism remaining in the field. (B) Starting of the prime mover. o (C) Providing current to the field from an external source. o (D) Residual magnetism remaining in the armature. If choice B is selected set score to After prior isolation and lock-out/tag-out procedures are performed, which electrical device requires discharging any stored electrical energy before any work may safely begin? o (A) potential transformer (B) capacitor o (C) resistor bank o (D) choke coil If choice B is selected set score to 1. 8/31/2017 Page 5 of 26

6 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: Referring to the illustrated pneumatically operated diaphragm actuated control valve, what statement is true? Illustration GS-0051 (A) The control valve is direct-acting and normally open (NO). o (B) The control valve is indirect-acting and normally open (NO). o (C) The control valve is direct-acting and normally closed (NC). o (D) The control valve is indirect-acting and normally closed (NC). 19. In comparing a semiconductor diode to a vacuum tube diode, what statement is true? o (A) The semiconductor diode has longer life, no warm-up time, and is more delicate than the vacuum tube diode. o (B) The semiconductor diode has longer life, longer warm-up time, and is less delicate than the vacuum tube diode. o (C) The semiconductor diode has shorter life, no warm-up time, and is less delicate than the vacuum tube diode. (D) The semiconductor diode has longer life, no warm-up time, and is less delicate than the vacuum tube diode. If choice D is selected set score to Which of the wave shapes shown in the illustration is termed a sinusoidal wave? Illustration EL-0088 (A) A o (B) B o (C) C o (D) D 21. Which of the figures illustrated is not suitable for use as a hex head set screw? Illustration GS-0080 o (A) figure G o (B) figure L o (C) figure C (D) figure D If choice D is selected set score to What is the name for the device shown in figure "A" of the illustration? Illustration EL-0064 o (A) direct current (DC) filter o (B) full-wave bridge rectifier (C) half-wave rectifier o (D) full-wave rectifier If choice C is selected set score to 1. 8/31/2017 Page 6 of 26

7 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: The amount of HCFC-123 in a storage cylinder is measured by what means? o (A) saturation pressure o (B) volume (C) weight o (D) saturation temperature If choice C is selected set score to Hot water heaters used in potable water systems may have multiple heat sources, such as an electric heating element and a jacket water heated tube bundle. What is the primary purpose of such an arrangement? o (A) Allow the designated backup heat source to be used in the event of failure of the designated primary heat source, whether in port or underway. o (B) Allow jacket water to be used in port and electricity to be used while underway. o (C) Allow both the heat sources to be used when the demand for hot water is high, whether in port or underway. (D) Allow electricity to be used in port and jacket water to be used while underway. If choice D is selected set score to The function of seal cages, or lantern rings installed in the centrifugal pump stuffing boxes, is to. o (A) cool the shaft o (B) lubricate the packing (C) distribute the sealing liquid within the stuffing box o (D) seal air from entering along the shaft If choice C is selected set score to What is used to protect a direct sensing steam pressure gauge from damage from contact with steam? o (A) The installation of a damping needle valve in the entrance to the gauge. o (B) The installation of a siphon tube (pig-tail) oriented horizontally in the entrance to the gauge. o (C) The installation of thermal insulation on the gauge. (D) The installation of a siphon tube (pig-tail) oriented vertically in the entrance to the gauge. If choice D is selected set score to 1. 8/31/2017 Page 7 of 26

8 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration system? o (A) high-pressure vapor (B) high-pressure liquid o (C) low-pressure vapor o (D) low-pressure liquid If choice B is selected set score to A reservoir, as used in hydraulic systems aboard ship, is used to store hydraulic oil. Another function is to. o (A) eliminate pressure surges in the system o (B) maintain the stored oil under pressure o (C) act as a shock absorber (D) act as a base or foundation for the power unit If choice D is selected set score to A reheater in an air conditioning system performs what function? (A) restores the conditioned air temperature to a comfortable level o (B) controls the inlet air volume o (C) controls the inlet air temperature o (D) maintains the relative humidity at 15% 30. What is the functional name of an electrical device which prevents simultaneous energization of loads thereby preventing damage or injury? o (A) monitoring device (B) electrical interlock device o (C) modulating device o (D) mechanical limit device If choice B is selected set score to Which of the following motors has a frame configuration for solid base mounting only? Illustration EL-0184 (A) A o (B) B o (C) C o (D) D 8/31/2017 Page 8 of 26

9 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: Concerning sentinel valves, what statement is true? o (A) The set point of the sentinel valve is usually above the maximum allowable working pressure of the system. o (B) The capacity of a sentinel valve must exceed the capacity of the pressure source. (C) The sentinel valve's sole purpose is to warn personnel of excessive system pressure. o (D) The set point of a sentinel valve is normally set below the normal working pressure of the system. If choice C is selected set score to Referring to the illustrated steam plant sea water cooling system drawing, which pump can be used to pump out the main machinery space bilge in a flooding emergency? Illustration SP-SW-01 (A) The two-speed main sea water circulating pump can be used for this purpose. o (B) The auxiliary sea water circulating pump can be used for this purpose. o (C) The single-speed main sea water circulating pump can be used for this purpose. o (D) Any of the sea water service pumps can be used for this purpose. 34. Liquid is kept from leaking out at the shaft ends of a helical gear pump by. (A) a stuffing box o (B) a roller bearing o (C) the use of shaft end caps o (D) overlapping spaces between gear teeth 35. Accidental flooding of the engine room bilges through the bilge system is prevented by. (A) stop-check valves installed in the bilge suction manifolds o (B) using a positive displacement reciprocating bilge pump o (C) installing eductors in all bilge rose boxes o (D) installing a swing check before each bilge valve 36. What statement is true concerning critical speeds associated with rotating machinery? o (A) The vibration amplitude is greatest at the second order critical speed. (B) The vibration amplitude is greatest at the first order (fundamental) critical speed. o (C) The vibration amplitude is greatest midway between 0 RPM and the first order (fundamental) critical speed. o (D) The vibration amplitude is greatest midway between the first order and the second order critical speed. If choice B is selected set score to 1. 8/31/2017 Page 9 of 26

10 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: A bearing temperature monitoring system such as that used for measuring selected propulsion plant bearings uses what technology? o (A) self-powered thermocouples o (B) self-powered resistance temperature detectors o (C) externally powered thermocouples (D) externally powered resistance temperature detectors If choice D is selected set score to Which of the projections represents the left side view of the object "X" in the illustration? Illustration GS-0022 (A) A o (B) B o (C) C o (D) D 39. A flare-type tubing connector is used in the hydraulic hatch cover system and has developed a slight leak. To stop the leak you should. (A) shut down the power unit and use two wrenches to avoid damaging the tubing when tightening o (B) replace both the tubing sections and the fitting o (C) keep the system in operation and tighten the flare nut o (D) stop the system and use only one wrench to tighten the flare nut 40. Which pair of safety disconnect switches shown in the illustration represents the exterior and interior views of a double-throw switch? Illustrations EL-0176 o (A) A and B (B) B and D o (C) C and D o (D) A and C If choice B is selected set score to For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? o (A) 100 F (B) 125 F o (C) 150 F o (D) 175 F If choice B is selected set score to 1. 8/31/2017 Page 10 of 26

11 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: To convert a vane type hydraulic pump to a hydraulic motor, which of the following would have to be done? (A) Provide small springs between the vanes and the base of the vane slots. o (B) Provide one additional slot and vane. o (C) Double the casing thickness. o (D) Install an enlarged control ring around the rotor. 43. Suppose that a standard remote reading bourdon tube thermometer has a scale of 40 to 240 o F. If the accuracy of the thermometer is plus or minus 1% of the span, what would the range of measured temperature be if the thermometer indicates 180 o F? o (A) to o F (B) 178 to 182 o F o (C) to o F o (D) 179 to 181 o F If choice B is selected set score to When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually throttle which valve? o (A) king valve (B) suction valve o (C) expansion valve o (D) sea water valve If choice B is selected set score to What is the drive arrangement of refrigeration compressor shown in figure "B" of the illustration? Illustration GS-RA-41 (A) welded, fully hermetic o (B) external-drive o (C) open o (D) serviceable, bolted, accessible semi-hermetic 46. What type of HVAC system is characterized by having control dampers in locations other than the outside air supply, outside air exhaust, and recirculation damper applications? o (A) A terminal reheat system o (B) A single zone system o (C) A dual duct system (D) A variable air volume system If choice D is selected set score to 1. 8/31/2017 Page 11 of 26

12 U.S.C.G. Merchant Marine Exam Assistant Engineer-MODU Illustrations: A centrifugal bilge pump requires priming. o (A) primarily to lubricate the shaft seals (B) due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller o (C) in order to overcome the potential energy of water in the discharge line o (D) to initially unload the pump by having its head pressure equal to discharge pressure If choice B is selected set score to As shown in figure "A" of the illustrated block diagram of a central operating system configured for direct digital control, what does the output system block "DIGITAL CONTACT" represent? Illustration EL-0095 o (A) It receives analog outputs from the analog device sensors and conditions these as analog signals for CPU processing. o (B) It receives digital outputs from the binary device sensors and converts these to analog signals for CPU processing. o (C) It receives analog outputs from the analog device sensors and converts these to digital signals for CPU processing. (D) It receives digital outputs from the binary device sensors and conditions these as digital signals for CPU processing. If choice D is selected set score to Energy losses occurring in a hydraulic system are ultimately absorbed by the. o (A) reservoir expansion chamber (B) atmosphere as heat o (C) hydraulic piping flexibility o (D) fluid as friction If choice B is selected set score to If an oily-water separator uses an inclined plate pack to facilitate separation, what statement concerning the plate pack is true? (A) The oil droplets collect on the underside of the plates and rise when they have reached the outer edge of the plate pack. Solid particles collect on the upperside of the plates and sink when they have reached the inner edge of the plate pack. o (B) The oil droplets collect on the upperside of the plates and sink when they have reached the outer edge of the plate pack. Solid particles collect on the underside of the plates and rise when they have reached the inner edge of the plate pack. o (C) The oil droplets collect on the upperside of the plates and rise when they have reached the outer edge of the plate pack. Solid particles collect on the underside of the plates and sink when they have reached the inner edge of the plate pack. o (D) The oil droplets collect on the underside of the plates and sink when they have reached the outer edge of the plate pack. Solid particles collect on the upperside of the plates and rise when they have reached the inner edge of the plate pack. 8/31/2017 Page 12 of 26

13 EL /2/2016 Adapted for testing purposes only Further reproduction prohibited without permission. Page 13 of 26

14 EL /2/2016 Adapted for testing purposes only Further reproduction prohibited without permission. Page 14 of 26

15 EL /6/2015 Adapted for testing purposes only from HUNT, Modern Marine Engineer s Manual, Vol. II Cornell Maritime Press. Reproduced with permission from Cornell Maritime Press, a division of Schiffer Publishing, Ltd. Further reproduction prohibited without permission. Page 15 of 26

16 EL /2/2016 Adapted for testing purposes only Further reproduction prohibited without permission. Page 16 of 26

17 EL /2/2016 Adapted for testing purposes only Further reproduction prohibited without permission. Page 17 of 26

18 GS /22/2015 Adapted for testing purposes only Further reproduction prohibited without permission Page 18 of 26

19 GS /14/2015 Adapted for testing purposes only from FEIRER, Machine Tool Metalworking Copyright 1961 by the McGraw Hill Book Company, Inc. Further reproduction prohibited without permission Page 19 of 26

20 GS /2/2016 Adapted for testing purposes only from MOLLAND The Maritime Engineering Reference Book Copyright 2008 by Elsevier Ltd. Further reproduction prohibited without permission Page 20 of 26

21 GS /30/2015 Adapted for testing purposes only from Engine Room Tools Copyright 1970 by School of Marine Engineering & Navigation District 2 MEBA AFL-CIO, Safety & Education Plan Further reproduction prohibited without permission Page 21 of 26

22 GS-0153 Adapted for testing purposes only from Operator, Unit and Direct Support Maintenance Manual Including Repair Parts and Special Tools List for Oil Water Separator TM & P Further reproduction prohibited without permission Page 22 of 26 5/24/2016

23 GS-RA-33 4/14/2017 Adapted for testing purposes only from CARR, Refrigerants and the Environment Copyright 1993 by John Carr Page 23 of 26 Further reproduction prohibited without permission

24 GS-RA-41 5/5/2017 Adapted for testing purposes only Further reproduction prohibited without permission Page 24 of 26

25 MP-CW-06 6/7/2016 Adapted for testing purposes only from HUNT, Modern Marine Engineer's Manual, Vol. II Copyright 2002 from Cornell Maritime Press, Inc. Further reproduction prohibited without permission Page 25 of 26

26 SP-SW-01 12/23/2015 Adapted for testing purposes only HARRINGTON, Marine Engineering Copyright 1992 by The Society of Naval Architects and Marine Engineers Further reproduction prohibited without permission Page 26 of 26