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Tidal Currents — Flood, Ebb, Set, Drift, Rotary Currents, Slack Water, Navigation Effects & NOAA Current Predictions
Navigation - Tides & Currents
At-Sea Lessons: Free Deck and Engine Samples
Read full sample lessons and maritime flashcards without signing in. These are lessons, not a practice exam.
Deck Lessons
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Watchkeeping, Lookout & Watch Relief — Bridge Discipline, Relative Bearings, Mooring Watch, Autopilot, Manning & Whale Avoidance
Watchkeeping & General Safety
Engine Lessons
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Engineering Units, Conversions & Measurement — SI Prefixes, Temperature, Volume, Pressure & Dimensional Reasoning
Engineering Fundamentals, Calculations, Materials & Drawings
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Heat Transfer, Specific Heat & Thermal Efficiency — Conduction, Convection, Radiation, BTU Relationships, Fuel Heat & Heat-Sink Effects
Thermodynamics, Heat Transfer & Steam Properties
Free Flashcards
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What is the stand-on vessel’s initial duty?
The stand-on vessel initially keeps course and speed. That stable behavior helps the give-way vessel predict the encounter and maneuver safely.
Stand-On Vessel: Three Decision PhasesFREE
What makes avoiding action effective under Rule 8?
Avoiding action should be positive, made in ample time and large enough to be readily apparent. With sufficient sea room, a substantial course alteration alone can be effective if it is made in good time and does not create another close-quarters situation.
Avoiding Action: Early, Substantial and VerifiableFREE
What are the basic arcs of masthead, sidelight and sternlight?
Masthead light 225°, each sidelight 112.5°, and sternlight 135° total—67.5° on each side of dead astern.
Sternlight Arc: 67.5° Each Side AsternFREE
When damage produces stern trim plus free-surface instability, what should be corrected first?
First remove harmful slack-tank free surface in a way that also improves trim; only then add additional ballast if needed and safe.
Damage Stability: Correct the Slack Tank FirstFREE
Why are low-altitude celestial sights vulnerable to unusual error?
Atmospheric refraction is greatest near the horizon and decreases rapidly as altitude increases; low-altitude sights are therefore more vulnerable to abnormal-refraction error.
Low-Altitude Sun Sights: Refraction RiskFREE
How is range estimated with a fixed remaining fuel quantity after a speed change?
First scale the known fuel per mile by the square of the speed ratio, then divide the remaining fuel by the new fuel-per-mile value.
Fuel, Speed and Endurance: Square-Law RangeFREE
What is damping in a control loop?
The progressive reduction or suppression of oscillation so the response settles.
Control Systems: Recognizing InstabilityFREE
What electrical property is commonly used to indicate salinity?
Electrical-conductivity measurement is a common basis for marine salinity indication because dissolved ionic salts increase water conductivity.
Salinity Indication: Why Conductivity MattersFREE
What is the purpose of the air cushion in a hydropneumatic potable-water tank?
A hydropneumatic pressure tank uses a compressed-air cushion to maintain pressure and reduce pump cycling. If the tank becomes waterlogged, the pump tends to start and stop in very short, frequent cycles.
Hydropneumatic Tanks: Recognizing WaterloggingFREE
What should you remember about cam-profile timing and lift?
Camshaft cam arrangement and cam profile establish firing sequence and directly control valve timing and valve lift.
Diesel Camshafts: Operating Conditions ControlledFREE
What energy does a hydraulic accumulator store?
A hydraulic accumulator stores potential energy by retaining hydraulic fluid under pressure, allowing short-duration flow or force when the pump is unloaded or stopped.
Hydraulic Accumulators: Stored EnergyFREE
How does synchronous-motor field excitation affect torque?
Increasing DC field excitation strengthens the rotor magnetic field and increases hold-in torque, subject to machine limits.
Synchronous Motors: Increasing Hold-In TorqueSign in for the existing daily library preview or Academy Pro. No paid library, saved history or member content is opened by these samples.