AB Cheat Sheet 2026

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

1. Under COLREGS Rule 18, which category of vessel has the highest priority in the give-way hierarchy? → Vessel not under command
2. What precaution must be taken BEFORE activating a CO2 total flooding system in an engine room? → Ensure all personnel have evacuated the space
3. What is the purpose of a ship's 'stripping pump' in cargo operations? → To remove the final residues of liquid cargo from tanks that main cargo pumps cannot reach
4. Which vessel is considered 'restricted in her ability to maneuver' under the COLREGS? → A vessel laying an underwater cable
5. What is a 'spring line' used for when mooring? → To prevent the vessel from moving forward or aft along the dock
6. What is meant by 'GM' in ship stability terminology? → The metacentric height — the distance between the center of gravity and the metacenter
7. What is a meteorological 'trough'? → An elongated area of low pressure
8. How is the 'metacentric height' (GM) of a vessel related to its stability? → A larger GM indicates a stiffer, more stable vessel with a faster rolling period
9. What is the 'safe working load' (SWL) of a line in relation to its breaking strength? → A fraction of breaking strength reduced by a safety factor
10. A seaman is painting a confined area below decks. The MOST important safety precaution is to: → Ensure adequate ventilation and wear appropriate respiratory protection
11. According to the International Regulations for Preventing Collisions at Sea, a vessel is considered to be 'underway' when she is: → Not at anchor, not made fast to shore, and not aground
12. What is the 'displacement' of a vessel? → The weight of water displaced by the hull, equal to the total weight of the vessel
13. You are on anchor watch and notice the vessel has dragged anchor. After alerting the master, your immediate duty regarding navigation is to: → Plot the new position and determine drift rate and direction
14. When a helmsman is steering by gyrocompass and the order 'meet her' is given, the helmsman should: → Apply opposite rudder to check the vessel's swing and steady on the new heading
15. What is the meaning of a black circle on the NFPA 704 hazard diamond (fire diamond)? → The material is water-reactive
16. What is the purpose of COLREGs? → Prevent collisions
17. What does a steady barometer generally indicate about upcoming weather? → Continued settled weather
18. Which statement about keeping a proper watch in port is correct? → A watch must be maintained at all times, even when in port, to ensure safety and security
19. When rigging a pilot ladder, which of the following is a critical SOLAS requirement? → The bottom four steps must be made of rubber or a resilient synthetic material.
20. What is the purpose of the 'Plimsoll mark' (load line mark) on a vessel's hull? → To indicate the maximum safe loading depth in various conditions and water types
21. A 'permit to work' system is primarily designed to: → Ensure hazardous tasks are formally authorized and controlled
22. A vessel is said to be 'hogging' when: → The bow and stern are higher than amidships, causing the keel to arch upward
23. What is a ship's compass used for? → Determine direction
24. What is heaving a line? → Throwing a small line
25. Flash point is defined as the lowest temperature at which a liquid: → Produces enough vapor to ignite momentarily when exposed to an ignition source
26. Nylon rope is preferred for anchor rodes and tow lines primarily because of its: → High elasticity that absorbs shock loads
27. What is the 'deadweight tonnage' (DWT) of a vessel? → The total weight of cargo, fuel, stores, crew, and passengers that a vessel can carry
28. When using a ring life buoy to rescue a person in the water, what is the correct technique? → Throw it just upwind or upcurrent of the person so it drifts to them
29. What is the purpose of a fire damper in a ship's ventilation system? → To prevent fire and smoke from spreading through ductwork
30. When a vessel is described as 'dragging anchor,' it means the anchor is: → Failing to hold and sliding along the bottom