Propulsion and Machinery Systems Flashcards

A surveyor inspects a pod drive vessel and notices the pod unit has significant play when pushed laterally by hand. This indicates:

Answer: Worn or failed pod drive mounting bearings requiring immediate evaluation

Lateral play in a pod drive unit indicates worn mounting bearings, which can lead to progressive damage to the pod drive, hull interface, and steering components.

When a marine surveyor observes blue smoke from a diesel engine exhaust during the sea trial, what is the most common cause?

Answer: Engine oil being burned in the combustion chamber due to worn rings or valve seals

Blue exhaust smoke is a reliable indicator that engine oil is entering the combustion chamber and being burned, typically from worn piston rings or valve guide seals.

What is the significance of measuring propeller blade pitch at the 0.7 radius station during a survey?

Answer: The 0.7 radius is the standard reference station for pitch measurement as it represents the effective working area of the blade

The 0.7 radius station (70% of blade length from hub) is the industry-standard reference point for measuring pitch because it represents the blade's most aerodynamically effective working section.

A vessel's engine room blower ventilation is found inadequate during survey. What is the primary operational consequence for a diesel engine?

Answer: Insufficient combustion air supply and inability to remove heat, leading to power loss and overheating

Diesel engines require substantial air volume for both combustion and engine room cooling; inadequate ventilation starves combustion and traps heat, causing power loss and accelerating engine wear.

During an engine room inspection, a surveyor finds the raw water seacock serving the engine cooling system is seized in the open position. What is the correct survey finding?

Answer: A deficiency requiring replacement; a seized seacock cannot be closed in an emergency or for service

A seized seacock is a significant safety deficiency because it cannot be closed to stop flooding if the connected hose fails or to facilitate maintenance.

What does a marine surveyor look for when evaluating flexible engine mounts during a propulsion system inspection?

Answer: Rubber element cracking, deformation, compression set, or oil saturation that reduces vibration isolation

Failed flexible mounts with cracked, oil-soaked, or collapsed rubber elements no longer isolate engine vibration, causing structural stress transmission to the hull and accelerated wear.

A surveyor evaluating a water-jet propulsion system notes the impeller wear ring clearance is at the maximum allowable limit. What operational effect should the owner expect?

Answer: Reduced thrust efficiency and higher fuel consumption as water bypasses the impeller through excess clearance

Excessive wear ring clearance allows pressurized water to recirculate from the pump discharge back to the inlet, reducing thrust output and increasing fuel consumption.