Karm Fork Ø600, Ø500 and Ø350, Towing pins Ø500, Ø450 and Ø350
Karm Fork Ø600, Ø500 and Ø350, Towing pins Ø500, Ø450 and Ø350 by Karmøy Winch AS. DNV TA certificate TAS000023X.
Inspector Detail
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Common issues
- Pin and fork bore wear (ovalization) from repeated towing load cycles
- Surface corrosion or pitting on load-bearing faces
- Fatigue cracking at high-stress fillets and shoulders, more likely on older units
- Retaining/locking mechanism wear allowing risk of accidental pin release
- Grease nipple blockage leading to dry, galled bearing surfaces
- Bending or permanent deformation from shock loading beyond rated capacity
- Coating/paint loss exposing bare steel to accelerated corrosion
Inspection checklist
- Visual check for surface cracks, especially at fillets and load-bearing shoulders
- Dimensional check of pin diameter and fork bore for wear or ovalization
- NDT (dye penetrant or magnetic particle) at fatigue-critical areas
- Locking/retaining device function check
- Corrosion and coating condition assessment
- Grease points serviced and free movement confirmed
- Confirm the marked safe working load is legible and matches certification
- Check for bending or permanent deformation against original dimensions
- Verify load-test/thorough-examination certificate is current and on board
Service intervals
| Visual inspection before use | each time before towing operations |
| Greasing of pin/bearing surfaces | per the maker's schedule, commonly at short intervals under frequent use |
| NDT crack inspection | typically annually or per the class/owner's lifting-gear inspection scheme |
| Load test / thorough examination | typically every 4-5 years or per class and flag requirements for towing gear, whichever is more frequent |
Typical wear limits
| Pin diameter wear | renew when diameter reduction reaches the maker's stated limit for this SWL class - typically a small percentage of nominal diameter; confirm the exact figure against the equipment's own certificate |
| Fork bore wear/ovality | renew or re-bush when ovality approaches the maker's stated limit for this SWL class - confirm against the equipment's documentation |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Retaining/locking pin or split pin set
- Grease nipples
- Replacement pin matched in diameter and material grade to the fork
- Corrosion protection coating system components
Safety
- Sudden failure under load can cause a whipping towline - keep personnel clear of the bight and snap-back zone
- Crush/pinch hazard when inserting or removing pins under any residual load
- Never exceed the marked safe working load
- Corroded, cracked, or worn pins/forks must be withdrawn from service, not worked around
Class survey
Towage appurtenances of this kind are normally covered under the ship's towage or cargo gear certification; class and flag typically require periodic thorough examination and proof/load testing with certificates retained on board, plus a visual check before each use.
Components & Design
Component data being added…
Technical Data
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