Free USCG General Engineering Questions and Answers — Questions and Answers
Question 1: The sizing of tubing is ____.
- cross-section area
- allowed working pressure
- nominal outside diameter (Correct answer)
- nominal inside diameter
Correct answer: nominal outside diameter
Tubing is typically sized by its nominal outside diameter (OD), unlike pipes which are often sized by nominal inside diameter (ID) or nominal pipe size (NPS). This convention is important for selecting appropriate fittings, clamps, and tools, as the external dimension is critical for connection and installation. The wall thickness then determines the actual inside diameter and pressure rating.
Question 2: When a refrigeration compressor is short cycled, ______ is meant.
- frequently starting and sopping (Correct answer)
- frequently grounding out
- running too slow
- running too fast
Correct answer: frequently starting and sopping
Short cycling in a refrigeration compressor refers to the system frequently starting and stopping in rapid succession. This often indicates a problem such as an oversized unit, low refrigerant charge, dirty coils, or a faulty thermostat/pressure switch. Short cycling is detrimental to the compressor's lifespan and energy efficiency, as it causes excessive wear and tear and consumes more power during startup.
Question 3: The normal usage of the emergency bilge suction valve is ____.
- if the bilges become flooded and they can not be emptied by any other means (Correct answer)
- to inject cleaning additives when the bilges are extremely dirty
- when the main condenser becomes fouled, in order to provide additional cooling water circulation
- to connect the rose box to the independent bilge suction
Correct answer: if the bilges become flooded and they can not be emptied by any other means
The emergency bilge suction valve is a critical safety feature designed to provide a last resort for dewatering the vessel's bilges. It is typically connected to the main circulating pump or another high-capacity pump, allowing rapid removal of large volumes of water in severe flooding situations when the regular bilge pumps are overwhelmed or inoperable. Its use is reserved for emergencies to prevent the vessel from sinking.
Question 4: The general by-products of oxidation caused by hydraulic il water contamination are ____.
- harmless and have no effect on system components
- removed by cellulose type filters
- gums, varnishes, and acids (Correct answer)
- always neutralized by oil additives
Correct answer: gums, varnishes, and acids
Water contamination in hydraulic oil, especially when combined with heat and oxygen, significantly accelerates the oil's oxidation process. This oxidation leads to the formation of harmful by-products such as gums, varnishes, and acids. Gums and varnishes can cause sticky residues and blockages, while acids corrode system components, leading to premature wear and system failure.
Question 5: The _____ must contain a list of the kinds and strengths of steels utilized on a MODU.
- builder's documentation
- Certificate of Inspection
- Construction portfolio (Correct answer)
- general plans
Correct answer: Construction portfolio
The Construction Portfolio for a Mobile Offshore Drilling Unit (MODU) is a comprehensive document that details the unit's structural design and materials. It specifically includes a list of the kinds and strengths of steels used in the MODU's construction. This information is crucial for ensuring structural integrity, compliance with design specifications, and for future maintenance and repair operations.
Question 6: Which of the following fittings has to be used when installing pipework so that the pump can be removed for maintenance?
- Union (Correct answer)
- Coupling
- Nipple
- Quick disconnect
Correct answer: Union
A union is a pipe fitting specifically designed to allow two pipes to be connected or disconnected without disturbing the rest of the piping system. This makes it ideal for installing components like pumps, valves, or filters that may need to be removed for maintenance or replacement. Unions consist of three parts that can be easily separated and reconnected, facilitating quick and efficient servicing.
Question 7: On a MODU, a continuous waterproof bulkhead can also be a _____.
- centerline bulkhead
- structural bulkhead (Correct answer)
- exterior bulkhead
- centerline bulkhead
Correct answer: structural bulkhead
On a Mobile Offshore Drilling Unit (MODU), a continuous watertight bulkhead often serves a dual purpose as a structural bulkhead. These bulkheads are integral to the vessel's strength and integrity, contributing to its overall structural framework while also providing watertight compartmentalization. This design ensures both stability and safety, especially in offshore environments.
Question 8: Which of the following best describes a striker or double plate's function?
- Prevents valve seem over travel
- Provides a surface for the application of force, or the installation of machinery
- Provides landing surface for the sounding bob of a tank sounding tap (Correct answer)
- Absorbs machinery vibration
Correct answer: Provides landing surface for the sounding bob of a tank sounding tap
A striker plate, also known as a double plate, is a reinforced plate installed at the bottom of a tank, directly beneath a sounding pipe. Its primary function is to provide a durable landing surface for the sounding bob (the weight attached to a sounding tape). This prevents the bob from damaging the tank bottom over time due to repeated impacts during sounding operations, ensuring the tank's integrity.
Question 9: In the case of a flash type evaporator, a high reading at a salinity cell situated in the loop seal between two stages would suggest ____.
- carryover in the first-stage (Correct answer)
- chill shocking is necessary to remove scale
- leakage at the second-stage condenser
- faulty operation of the brine overboard pump
Correct answer: carryover in the first-stage
In a flash-type evaporator, the loop seal between stages is designed to prevent vapor from bypassing the intended flow path and to maintain pressure differentials. A high salinity reading in this loop seal suggests that brine (high-salinity water) is being carried over from the first stage into subsequent stages. This "carryover" indicates inefficient separation of vapor from the concentrated brine, leading to higher salinity in the distillate or downstream stages.
Question 10: In terms of MODU construction, the quarters' bulkheads are typically ___.
- continuous
- non-structural (Correct answer)
- watertight
- structural
Correct answer: non-structural
On a Mobile Offshore Drilling Unit (MODU), the bulkheads within the quarters (accommodation areas) are typically non-structural. This means they are not designed to bear the primary loads of the vessel's hull or superstructure. Their main purpose is to divide interior spaces, provide privacy, and offer some fire and sound insulation, rather than contributing to the unit's overall strength or watertight integrity.
Question 11: A center gage is used in machine shop practice to verify the angle of ____.
- screw threads
- drill points
- 60 degree thread cutting tools (Correct answer)
- screw thread pitch
Correct answer: 60 degree thread cutting tools
A center gage, also known as a thread center gage or screw pitch gage, is a specialized tool used in machine shops. Its primary function is to accurately verify the angle of a 60-degree thread cutting tool before it is used to cut screw threads. This ensures that the cutting tool has the correct profile to produce threads with the standard 60-degree included angle, which is critical for proper thread engagement and strength.
Free USCG General Engineering Questions and Answers
The sizing of tubing is ____.