🔍 Key Concepts

• Non-destructive testing (NDT) methods used on ship tail shafts • Difference between liquid penetrant dye testing and magnetic flux (magnetic particle) testing • Material requirements (e.g., ferromagnetic vs non‑ferromagnetic metals) for each test

💭 Think About

• What type of material is a typical tail shaft made from, and does it respond to magnetic fields? • Which of the listed methods relies on capillary action into surface-breaking defects, and which relies on distortion of a magnetic field by a crack? • Are these methods mutually exclusive, or can more than one be appropriate for detecting surface cracks on a shaft?

✅ Before You Answer

• Verify whether a tail shaft is usually a ferromagnetic steel component or a non‑magnetic alloy in standard exam assumptions. • Check which NDT method requires the part to be magnetizable to work properly. • Confirm whether both methods are suitable for detecting surface cracks, provided the material requirements are met.