SAMS - Society of Accredited Marine Surveyors Certified Propulsion and Machinery Systems Questions and Answers 1 — Questions and Answers
Question 1: A marine surveyor is inspecting a diesel engine that is producing excessive black smoke. Which of the following is the MOST likely cause?
- Water in the fuel
- Coolant leaking into the combustion chamber
- An improper air-to-fuel ratio (Correct answer)
- The engine is not reaching operating temperature
Correct answer: An improper air-to-fuel ratio
Black smoke from a diesel engine is a classic sign of incomplete combustion, which is most often caused by an improper air-to-fuel ratio where there is too much fuel or not enough air. Common culprits include clogged air filters, faulty fuel injectors, or a malfunctioning turbocharger. White smoke often indicates water or coolant issues, while blue smoke points to burning oil.
Question 2: During a pre-purchase survey of a vessel with an inboard engine, you observe a traditional stuffing box dripping water at a rate of 15-20 drops per minute while the shaft is stationary. What is the appropriate recommendation to the client?
- This is a normal and acceptable condition.
- The packing gland nut should be loosened slightly.
- The vessel requires an immediate haul-out to replace the cutless bearing.
- The packing gland nut should be tightened until the dripping stops completely with the shaft static. (Correct answer)
Correct answer: The packing gland nut should be tightened until the dripping stops completely with the shaft static.
A traditional stuffing box is designed to leak slightly (a few drops per minute) when the shaft is turning to provide lubrication and cooling to the packing material. However, it should not drip, or drip minimally, when the shaft is stationary. Excessive dripping when stopped indicates the packing is too loose. The correct action is to tighten the packing gland nut just enough to stop the leak when the shaft is not turning. Over-tightening can cause the packing to overheat and score the shaft when underway.
Question 3: Which of the following is a primary advantage of an Impressed Current Cathodic Protection (ICCP) system over a sacrificial anode system?
- Lower initial installation cost.
- Requires no external power source to operate.
- It is a completely passive and maintenance-free system.
- Allows for precise control and adjustment of the protection level. (Correct answer)
Correct answer: Allows for precise control and adjustment of the protection level.
ICCP systems use a rectifier to provide a controlled DC current to inert anodes, allowing for precise adjustment of the protection level to match changing environmental conditions like salinity and temperature. Sacrificial anode systems are passive, relying on the natural galvanic potential between different metals, and their output is fixed and not adjustable. ICCP systems have a higher initial cost and require an external power source and more regular maintenance compared to sacrificial systems.
Question 4: A surveyor inspecting a vessel's steering gear system in accordance with SOLAS and USCG regulations should verify which of the following?
- The hydraulic fluid was changed within the last 12 months.
- The presence of audible and visual alarms for power failure and hydraulic fluid low-level. (Correct answer)
- The system is capable of moving the rudder from 35 degrees on one side to 35 degrees on the other in less than 15 seconds.
- The tiller arm is painted with high-visibility yellow paint.
Correct answer: The presence of audible and visual alarms for power failure and hydraulic fluid low-level.
Regulations such as 46 CFR 58.25-25 require specific audible and visual alarms for the steering gear. These include alarms in the pilothouse and machinery space for power failure to the power unit or control system, and for low hydraulic fluid levels. While rudder movement speed is tested (typically 35 degrees to 30 degrees in 28 seconds), the 15-second parameter is not a standard requirement. Fluid change intervals and paint color are maintenance and company practices, not specific regulatory alarm requirements.
Question 5: During a sea trial on a twin-engine vessel, you note significant vibration from the port shaft at cruising RPM, which was not present at lower speeds. The propeller was reported to be recently balanced. Which of the following is the most probable cause that requires further investigation?
- A fouled hull surface increasing drag.
- Incorrect fuel grade being used for the engine.
- Misalignment between the engine and propeller shaft. (Correct answer)
- A malfunctioning bilge pump in the engine room.
Correct answer: Misalignment between the engine and propeller shaft.
Vibration that increases with RPM, especially after confirming the propeller is in good condition, is a classic symptom of misalignment. The alignment between the engine, transmission, and propeller shaft is critical. Misalignment can cause the shaft to whip at higher speeds, leading to vibration, wear on cutless bearings, and potential damage to the transmission or engine mounts. The other options are unlikely to cause localized, shaft-specific vibration.
Question 6: When inspecting a wet exhaust system on a recreational vessel, which of the following is a critical safety-related finding that must be reported?
- The use of non-metallic mufflers.
- A single hose clamp securing the exhaust hose to the manifold riser. (Correct answer)
- Presence of a high-rise exhaust elbow.
- Exhaust hose routing that includes a gradual bend.
Correct answer: A single hose clamp securing the exhaust hose to the manifold riser.
According to ABYC P-1 standards, every exhaust hose connection must be secured with at least two non-overlapping hose clamps to ensure a liquid- and vapor-tight seal. A single clamp can create a pinch point and is a common cause of exhaust leaks, which can introduce dangerous carbon monoxide into the vessel. Non-metallic (fiberglass) mufflers, high-rise elbows, and gradual bends are all common and acceptable components of a properly designed wet exhaust system.
SAMS - Society of Accredited Marine Surveyors Certified Propulsion and Machinery Systems Questions and Answers 1
A marine surveyor is inspecting a diesel engine that is producing excessive black smoke.
Which of the following is the MOST likely cause?