Answer
Types of Crane Surveys
Standard lifting appliance surveys fall into periodic regulatory schedules and specialized condition assessments:
A. Initial Survey & Certification
- When: Executed during vessel construction or upon installing a new crane.
- Scope: Verification of design approval, materials, non-destructive testing (NDT) of critical welds, shop testing of hydraulic motors/winches, and an initial Proof Load Test (typically 25%–50% above the Safe Working Load/SWL) supervised by Class.
- Outcome: Issuance of the Form No. 2 (Register of Lifting Appliances and Cargo Handling Gear) and the initial Class certificate.
B. Annual / Periodic Survey
- When: Every 12 months (typically aligned with the vessel's Class Annual Survey).
- Scope:
- Thorough visual examination of structural jib/boom, pedestal, slewing column, and wire ropes.
- Operational functional test under normal working loads.
- Inspection of limit switches (hoisting limit, luffing limit, slewing limit, anti-two-block).
- Verification of brake holding power, emergency stop mechanisms, and hydraulic system leakage/pressures.
- Review of the Chain Register / Rigging Register log entries.
C. Quadrennial / 5-Year Major Survey & Load Test
- When: Every 5 years (aligned with Class Renewal Survey).
- Scope:
- Proof Load Testing: Subjecting the crane to a static/dynamic proof load using calibrated water bags or test weights per Class/ILO limits:
- SWL≤20 tonnes: Test Load = 1.25×SWL
- 20 tonnes<SWL≤50 tonnes: Test Load = SWL+5 tonnes
- SWL>50 tonnes: Test Load = 1.10×SWL
- Structural NDT: Magnetic Particle Testing (MPT) or Ultrasonic Testing (UT) on high-stress areas (jib heel pins, slewing ring foundation bolts, crane pedestal welds).
- Slewing Bearing Clearance: Measurement of tilting backlash (rocking test) to assess slewing ring bearing wear.
- Wire Rope & Sheave Renewal: Inspection/replacement of hoist and luffing wires; checking sheave groove dimensions.
- Proof Load Testing: Subjecting the crane to a static/dynamic proof load using calibrated water bags or test weights per Class/ILO limits:
D. Condition-Based / Damage Survey
- When: Conducted after a heavy contact/collision, dropped load incident, overstressing, or visible structural deformation.
- Scope: Structural alignment checks, thickness measurements, flaw detection, and mandatory re-load testing prior to returning the gear to service.