Mixed Deck — All MTC Topics Flashcards

A marine diesel engine produces white smoke from the exhaust at operating temperature. The MOST likely cause is:

Answer: Coolant or water entering the combustion chamber

White smoke at operating temperature in a diesel typically indicates coolant or water burning in the cylinder, pointing to a head gasket failure, cracked head, or injector sleeve leak.

What is the function of the shift interlock on a marine transmission?

Answer: Prevents shifting above a preset RPM to protect the gearbox

The shift interlock prevents engagement of forward or reverse above a safe RPM threshold, protecting the clutch packs and transmission internals.

What is the purpose of a pressure-accumulator tank in a pressurized marine freshwater system?

Answer: To store air pressure that maintains water pressure and reduces constant pump cycling

A pressure-accumulator tank stores compressed air that maintains system pressure between demand cycles, reducing pump wear and providing smoother, more consistent water flow.

Which ABYC standard governs the installation of electrical systems on boats?

Answer: ABYC E-11

ABYC E-11 is the standard for AC and DC electrical systems on boats, covering wiring, overcurrent protection, and installation practices.

A vessel operating in a North American Emission Control Area (ECA) must use fuel with a maximum sulfur content of:

Answer: 0.10%

Within the North American ECA, MARPOL Annex VI requires fuel sulfur content not to exceed 0.10% m/m.

What is the standard torque specification approach when reassembling a propeller nut?

Answer: Torque to manufacturer specification and install a cotter pin through the castle nut

The propeller nut must be torqued to spec and secured with a cotter pin through the castle nut and shaft hole to prevent loosening under reverse loads.

When selecting a replacement propeller, which two specifications are MOST critical to match for correct engine loading?

Answer: Diameter and pitch

Diameter determines thrust and RPM band while pitch controls the theoretical advance per revolution; together they define the propeller's load on the engine and must match the power and application.

In MTC practice, what is the purpose of a standard operating procedure (SOP)?

Answer: To document step-by-step instructions for routine tasks to ensure consistency and quality

SOPs provide standardized, detailed instructions for routine operations, ensuring consistency, quality, efficiency, and safety regardless of which qualified individual performs the task.

What causes a propeller shaft to vibrate excessively at higher RPM on an inboard vessel?

Answer: Shaft misalignment or a bent/damaged propeller

A bent shaft or damaged propeller creates an unbalanced rotating mass that produces vibration that worsens as RPM increases.

What is the importance of continuing education in MTC professional practice?

Answer: To maintain current knowledge, meet certification requirements, and adapt to evolving industry standards

Continuing education ensures professionals stay current with new developments, technologies, and best practices in their field while fulfilling certification renewal requirements and providing better service to clients.

What is the function of an anti-siphon valve installed on a marine fuel system?

Answer: It prevents fuel from siphoning from the tank into the engine compartment if a line is broken

An anti-siphon valve opens only when the fuel pump is running, preventing gravity-fed fuel flow into the bilge if a downstream line fails, reducing fire risk.

When bleeding a hydraulic steering system on a marine vessel, what is the correct procedure?

Answer: Attach a vacuum pump to the fill port while turning the wheel lock-to-lock

Using a vacuum pump at the fill port while cycling the steering wheel lock-to-lock draws air bubbles out of the system and allows clean fluid to fill all passages.

Which of the following should be worn when grinding or cutting metal parts?

Answer: Safety goggles

When grinding or cutting metal, sparks, metal fragments, and abrasive particles are forcefully ejected. Safety goggles provide essential protection for the eyes against these high-velocity projectiles. This prevents serious eye injuries, which could range from minor irritation to permanent vision loss.

A vessel's hydraulic steering feels spongy and requires excessive effort to turn. After confirming adequate fluid level, the NEXT diagnostic step is:

Answer: Bleed air from the hydraulic system starting at the cylinder ends

Air trapped in hydraulic lines compresses, causing spongy feel; proper bleeding restores firm, responsive steering.

What is 'permeation' as it relates to marine sanitation hoses?

Answer: Sewage odors migrating through the hose wall itself even without visible leaks

Permeation occurs when odor molecules migrate through the hose material even when the hose appears intact, which is why sanitation-rated hose with an odor barrier is essential.

A stern-drive unit vibrates heavily at speeds above 3,000 RPM but is smooth at idle. The most likely cause is:

Answer: A damaged or out-of-balance propeller

Propeller imbalance or damage creates centrifugal vibration that intensifies with RPM, not present at low speeds.

A NMEA 2000 network on a vessel shows intermittent data dropouts on the chartplotter. The backbone appears properly terminated. What should the technician check next?

Answer: Backbone cable total length and individual T-connector seating and pin condition

Intermittent NMEA 2000 dropouts with proper termination usually stem from corroded or unseated T-connector pins or backbone length exceeding specification.

On a marine diesel engine, what is the purpose of the injection advance mechanism?

Answer: Advance injection timing as engine speed increases for optimum combustion

The injection advance mechanism advances fuel injection timing as RPM increases to compensate for the shorter time available for ignition delay and combustion.

A PM inspection of a marine vessel's safety equipment reveals that flare expiration dates have passed. Under USCG regulations, what is the correct course of action?

Answer: Expired flares must be disposed of properly and replaced with current, unexpired USCG-approved signals

USCG regulations require that visual distress signals be current (unexpired); expired flares may be carried as extras but cannot count toward the required complement.

On a marine depth sounder, the transducer sends and receives which type of energy?

Answer: Ultrasonic sound waves

Depth sounders use ultrasonic (high-frequency sound) pulses that travel through water and reflect off the bottom to calculate depth.