AB Study Guide 2026
Everything you need to pass the AB exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 AB Exam Format at a Glance
📚 AB Topics to Study (21)
✍️ Sample AB Questions & Answers
1. How should vessels pass when meeting head-on?
COLREGs Rule 14, concerning head-on situations, states that when two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, each shall alter her course to starboard. This action ensures that each vessel passes on the port side of the other, effectively preventing a collision.
2. When taking a vessel's mooring lines to a dock, the correct order for making fast is typically:
Standard practice is to first secure the bow and stern lines to prevent the vessel drifting away, then springs and breast lines to fine-tune position.
3. Which of the following structural members are considered the 'ribs' of the ship, providing the primary transverse strength to the hull?
Frames are the transverse ribs of a ship that are attached to the keel. They give the hull its shape and provide the main strength to resist pressure from the surrounding water, acting as the primary transverse stiffeners for the shell plating.
4. When is a vessel's GM considered 'positive'?
A vessel has positive GM when M is above G, producing a righting moment that returns the vessel toward upright when heeled.
5. What is the 'center of buoyancy'?
The center of buoyancy (B) is the geometric center of the submerged hull volume, through which the upward buoyant force acts.
6. What is 'free surface effect'?
Free surface effect is the reduction in effective stability caused by liquid in a partially filled tank shifting as the vessel heels, effectively raising G.