🔍 Key Concepts

• Free surface effect and how it reduces transverse (side-to-side) stability • The difference between a tank/space on the centerline versus off-center • What makes free surface effect most dangerous in terms of location of the flooded space

💭 Think About

• Picture a partially flooded compartment and imagine the ship rolling: where does the water move, and how does that movement affect the ship’s ability to come back upright? • Compare what happens if the water can move side-to-side in a tank right on the centerline versus in a tank located to port or starboard. • Ask yourself: does full flooding (no free surface) cause more or less loss of stability than partial flooding with a free surface?

✅ Before You Answer

• Verify which option describes a condition where the center of gravity shifts sideways with roll because the water can move transversely. • Check which situation creates a heeling moment when the vessel rolls, instead of just reducing GM symmetrically. • Make sure you distinguish between: loss of stability from free surface itself vs. the separate issue of being open to the sea.