1. Check the Identification Markings

Every shackle should have legible markings including:

• Manufacturer’s name or trademark

• Working Load Limit (WLL)

• Size

• Grade or standard (e.g., BS, ASME, or EN)
  If any marking is missing or illegible, the shackle should be removed from service.

2. Inspect for Deformation

Look for any bending, twisting, or spreading of the bow or pin. Even slight deformation can weaken the shackle significantly and indicates it’s already been overstressed.

3. Examine the Pin Threads

Check that the threads on the pin and inside the shackle body are clean, undamaged, and not worn out. Misaligned or stripped threads can cause the pin to loosen under load.

4. Confirm Full Engagement of the Pin

Make sure the shackle pin engages fully and properly. For screw pins, this means it must be screwed in completely. For bolt-type shackles, ensure cotter pins or split pins are in place and secure.

5. Look for Excessive Wear

Over time, shackles wear down, especially in high-use environments. Measure the diameter of the bow and the pin. If it has worn more than 10% from its original size, it’s no longer safe to use.

6. Check for Corrosion or Rust

Surface rust may be manageable, but deep corrosion pits or metal flaking can compromise the integrity of the shackle. Severely corroded shackles should be retired.

7. Inspect for Cracks or Fractures

Use visual inspection or non-destructive testing (NDT) methods like magnetic particle or dye penetrant testing to detect hairline cracks that are not visible to the naked eye.

8. Ensure Proper Fit and Compatibility

The shackle must fit properly with the other rigging gear (slings, hooks, etc.) without excessive side-loading. Improper fits can lead to unexpected load shifts or failure.

9. Avoid Unauthorized Modifications

Check that the shackle has not been altered — no welding, drilling, or grinding. Modified shackles lose their certified integrity and should not be used.

10. Observe for Signs of Misuse

Look for indications of past misuse such as:

Conclusion

Shackles are often overlooked because of their size, but they are foundational to load-handling safety. By performing these 11 inspections regularly, you:

• Prevent rigging failures

• Extend the life of your lifting gear

• Comply with international safety standards

Remember: If in doubt, take it out. It’s safer to replace a questionable shackle than to risk lives or damage.