Answer
| Feature | Initial Survey | Renewal Survey |
|---|---|---|
| Timing & Trigger | Carried out before the ship is put into service (New building, major structural conversion, or change of Flag). | Conducted at specified intervals, not exceeding 5 years, to renew statutory certificates. |
| Structural Scope | Complete, exhaustive verification of all construction plans, scantlings, material test certificates, and welding quality from scratch. | Focuses on structural wear. Involves extensive Ultrasonic Thickness (UT) gauging, close-up tank inspections, and searches for deformation, fractures, or corrosion. |
| Machinery Scope | Complete inspection of installations, shaft alignments, validation of entire piping layouts, pressure testing of all systems, and full sea trials to establish baseline performance. | Functional and operational testing. Selective opening up of key machinery components (pistons, bearings, boilers) based on running hours and the Class continuous survey cycle. |
| Testing Intensity | Prototype validation, heavy load-testing of all lifting gear, full safety matrix validation, and hydrostatic testing of all tanks. | Focuses on safety cutouts, insulation resistance (megger testing), functional tests of emergency systems, and operational verification. |