Accident due to broken suspension link
In this article, we were alerted by Korean Register about a serious incident that happened during a Rescue boat davit & winch operational test, which resulted in the Rescue boat dropping and a PSC detention.
The cause of the incident was a failure of one side of the Suspension Link & Block, which was holding the weight of the Rescue boat. The broken Chain Link was thinner than the required thickness specified by the manufacturer's manual. You can see the following images for more details.
This incident reminds us of the importance of following the agreement and IMO Res. MSC 402(96), which require a thorough inspection of Suspension Link & Block. Here are some precautions given by Korean Register:
- Report any non-compliance issues during the inspection to the Classification Society surveyor as soon as possible.
- Check the condition of Suspension Link & Block (corrosion and wear) according to the manufacturer's manual.
- Monitor for abnormal vibrations and noise during Davit & Winch operational tests.
- Be extra careful during the 5-year periodic inspection.
Additional precaution from our experience as a former lifeboat service provider:
- Always replace with genuine parts. Request for load test certificate from manufacturer.
- Davit Manufacturer Mansei Inc recommends a replacement once every 15 years for their suspension link and block, due to strength degradation. So, this can act as a guideline.
- We also suggest replacing them once a 10% loss is noticed.
Please review these preventive measures and make sure that we avoid such accidents in the future. This kind of accident can be easily prevented if the manufacturer's guidelines are followed and affected part was replaced.
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FAQ
What caused the rescue boat to drop during the davit and winch operational test?
One side of the suspension link and block failed while holding the rescue boat's weight, causing the boat to drop and a PSC detention. The broken chain link was thinner than the manufacturer's specified thickness: 20-21mm actual versus 25mm required.
What inspection checks are recommended for the suspension link and block?
Check the suspension link and block for corrosion and wear according to the manufacturer's manual, and report any non-compliance to the Classification Society surveyor promptly. During davit and winch operational tests, monitor for abnormal vibrations and noise, and take extra care during the 5-year periodic inspection.
How often should the suspension link and block be replaced?
Mansei Inc recommends replacing their suspension link and block once every 15 years because of strength degradation, which can act as a guideline. The post also suggests replacement once a 10% loss is noticed, alongside checking corrosion and wear according to the manufacturer's manual.
What does IMO Res. MSC 402(96) require for suspension link and block inspection?
IMO Res. MSC 402(96) requires a thorough inspection of the suspension link and block. The post links this to the importance of following the agreement covering inspection, and notes that non-compliance found during inspection should be reported to the Classification Society surveyor as soon as possible.
Should genuine parts and a load test certificate be used for suspension link replacement?
Yes. Replace with genuine parts, and request a load test certificate from the manufacturer. Following the manufacturer's guidelines and replacing the affected part can prevent this type of accident, according to the post, which also stresses inspection and correct replacement.