Maritime and Marine Cheat Sheet 2026

The 30 highest-yield Maritime and Marine facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is 'apparent wind' on a sailing vessel? → The combination of true wind and the wind created by the vessel's own movement
2. What is hypothermia, and at what water temperature does it become a serious risk within one hour? → Dangerous drop in body core temperature; water below 60°F (15°C)
3. Under the Jones Act (Merchant Marine Act of 1920), what is required for cargo transported between US ports? → Cargo must be carried on US-built, US-owned, and US-crewed vessels
4. Under the International Rules (COLREGS), what does a vessel display when she is not under command? → Two all-round red lights in a vertical line
5. What is 'way' as used in maritime terminology? → The movement of a vessel through the water
6. What does a red sky at morning indicate for mariners according to traditional weather lore — and meteorological science? → Moisture-laden air and dust moving in from the west, often preceding rain or storms
7. What is the USCG requirement for a Type IV throwable PFD on recreational vessels? → Required on all vessels 16 feet or longer in addition to wearable PFDs
8. What is the function of a seacock (sea valve) on a vessel? → To shut off a through-hull fitting to prevent flooding if a hose or fitting fails
9. How does a tropical storm become classified as a hurricane in the Atlantic? → Sustained winds reach 74 mph (64 knots) or greater
10. On a nautical chart, what does an anchor symbol enclosed in a circle indicate? → A recommended anchorage area
11. What is the purpose of a 'Notice to Mariners' published by the National Geospatial-Intelligence Agency (NGA) and USCG? → To issue corrections and updates to nautical charts and publications
12. What is 'dead reckoning' in marine navigation? → Estimating current position from a known fix using course, speed, and elapsed time
13. What signal is used by a power-driven vessel leaving a dock under Inland Rules? → One or two short blasts depending on direction of turn
14. When thunderstorms are present, what is the safest action for a small boater? → Return to shore immediately and seek shelter away from water
15. What does a two-stroke outboard engine require that a four-stroke engine does not? → Oil premixed with the fuel or injected by a separate oil injection system
16. What is the Mayday radio call procedure on VHF Channel 16? → Say 'Mayday' three times, vessel name three times, then position and nature of distress
17. Which flare type is most effective for signaling rescuers at night at close range? → Hand-held red flare
18. Which nautical chart scale would a mariner use for the most detailed view of a harbor or anchorage? → Harbor chart (1:50,000 or larger)
19. What does the term 'fetch' mean in weather and wave forecasting? → The distance over which wind blows across open water to build waves
20. What does a vessel constrained by her draft display in addition to normal running lights? → Three all-round red lights in a vertical line
21. How many persons-on-board (POB) must be reported when filing a float plan? → The exact count of all persons aboard
22. What is the US Coast Guard recommended capacity label on a recreational boat? → Maximum number of persons, maximum weight, and maximum horsepower
23. What causes sea fog (advection fog) common along the US coasts? → Warm moist air moving over cooler water, cooling to its dew point
24. When using a GPS chart plotter near hazards, what is the most critical consideration to avoid position errors? → Verifying the GPS datum matches the chart datum
25. What does 'COG' indicate on a GPS or chart plotter display? → Course Over Ground
26. What is a navigational 'range' used for? → Aligning two fixed marks to guide a vessel along a safe track
27. What is the recommended action when a marine diesel engine shows a sudden drop in oil pressure? → Stop the engine immediately to prevent catastrophic bearing failure
28. What is the purpose of a bilge pump aboard a vessel? → To remove accumulated water from the lowest part of the vessel's hull
29. What is the minimum age to operate a PWC (personal watercraft) without supervision in most US states? → 16 years old
30. What is required when a boating accident results in a death or disappearance of a person? → Report verbally to the Coast Guard within 24 hours and file written report within 10 days