🔍 Key Concepts

• Effect of shifting weights longitudinally (forward or aft) on a vessel’s trim • Difference between rolling (side-to-side motion) and yawing (swinging off course/heading) • Behavior of a vessel running before a heavy sea and the risk of broaching-to

💭 Think About

• Ask yourself: When you move weights aft, does the ship’s trim change by the bow or by the stern, and how could that affect how well the vessel holds a straight course in following seas? • Consider whether a fore-and-aft shift of weight mainly affects side-to-side motion (rolling) or heading/track stability (yawing). • Think about what motion is most dangerous when running before a heavy sea: is it excessive rolling, or the tendency for the stern to be pushed around so the vessel slews off course?

✅ Before You Answer

• Be clear on the definitions: rolling = side-to-side, yawing = swinging of the bow left/right around a vertical axis. • Verify which motion is more directly influenced by trim (bow vs stern) rather than by transverse stability (GM and beam). • Check which choice matches the idea that trimming the vessel more by the stern can improve tracking and reduce the risk of broaching-to in following seas.