🔍 Key Concepts

• Permanent magnetism vs. induced magnetism in a steel ship • Difference between hard iron and soft iron magnetism • When during a ship's life the permanent magnetic field is mainly acquired

💭 Think About

• Ask yourself: which choice describes something that would create a lasting, built‑in magnetic field in the ship’s structure, even when the ship changes heading? • Which answers talk about effects that are temporary and change with the ship’s course or the local magnetic field, rather than staying fixed? • Think about when the ship’s steel is first strongly magnetized: is it during normal operations at sea, or earlier in the ship’s life?

✅ Before You Answer

• Identify which option specifically mentions hard iron (steel that retains magnetism) instead of soft iron. • Eliminate any options that clearly describe induced magnetism (magnetism that changes with heading or location). • Focus on the time frame: which option happens once and lasts, rather than continuously changing with operation or the ship’s orientation?