A davit-launched liferaft is a critical piece of lifesaving equipment used on ships and offshore installations. To ensure its reliability in an emergency, weight testing is a crucial part of regular maintenance and safety checks. But what does weight testing involve? When and how should it be done?
This topic will explain the importance of weight testing a davit-launched liferaft, the testing procedures, and key safety considerations.
What Is a Davit-Launched Liferaft?
A davit-launched liferaft is a type of inflatable survival craft stored in a canister and deployed using a davit system. Unlike standard throw-overboard liferafts, this system allows crew members to board the raft before lowering it into the water, making it safer in rough conditions.
Key Components of a Davit-Launched Liferaft:
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Liferaft Canister – A container holding the inflatable raft.
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Davit System – A mechanical arm used to lower the raft safely into the water.
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Lifting Hook and Release Mechanism – Ensures the raft is securely lifted and released at the right time.
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Inflation System – Automatically inflates the raft when needed.
Why Is Weight Testing Important?
Regular weight testing ensures that the davit system can safely lower a fully loaded liferaft without failure. It helps to:
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Verify Load Capacity – Ensures the davit system can support the liferaft’s full capacity.
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Identify Mechanical Issues – Detects potential failures before an emergency occurs.
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Comply with Regulations – Fulfills SOLAS (Safety of Life at Sea) requirements for liferaft testing.
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Enhance Crew Safety – Ensures that in an emergency, the liferaft will function as intended.
When Should Weight Testing Be Conducted?
Weight testing is required at specific intervals to maintain compliance with maritime regulations and ensure safety.
SOLAS and IMO Requirements
According to SOLAS (International Convention for the Safety of Life at Sea) and IMO (International Maritime Organization) regulations, davit-launched liferafts must undergo weight testing:
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During initial installation of the davit system.
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At least once every five years as part of major safety inspections.
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After any major repairs or modifications to the davit system.
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If there are concerns about structural integrity or operational efficiency.
Some companies may perform tests more frequently as part of their internal safety policies.
How to Perform Weight Testing on a Davit-Launched Liferaft
1. Pre-Test Preparations
Before conducting weight testing, proper preparations must be made to ensure safety and accuracy.
Safety Precautions:
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Conduct testing in calm weather with minimal external risks.
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Ensure all crew members are properly trained in weight testing procedures.
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Inspect the davit system, winch, and liferaft canister for visible damage.
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Secure the testing weights properly to avoid accidents.
Equipment Required:
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Certified test weights (equivalent to the full capacity of the liferaft).
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Lifting slings and shackles to attach weights securely.
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Safety harnesses and fall protection for personnel involved.
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Emergency stop mechanisms in case of equipment failure.
2. Conducting the Weight Test
Once preparations are complete, the weight test can be performed in a controlled manner.
Step-by-Step Weight Testing Procedure:
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Attach Test Weights
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Securely attach weights equivalent to the liferaft’s full capacity to the davit’s lifting mechanism.
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Ensure the weights are evenly distributed to simulate real conditions.
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Lift the Weights Using the Davit System
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Activate the lifting mechanism to raise the weights to the required height.
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Observe for any mechanical strain or unusual noises.
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Hold the Load for a Specified Time
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The davit must hold the full load for a specific duration (usually 5-10 minutes).
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Check for any structural weakness or signs of failure.
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Lower the Weights Safely
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Gradually lower the weights back to the ground or test platform.
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Observe for any issues with the winch or braking system.
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Inspect the Davit System Post-Test
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Conduct a detailed inspection for any signs of wear, deformation, or damage.
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Document any findings and schedule repairs if needed.
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Common Issues Detected During Weight Testing
Weight testing can reveal potential weaknesses in the davit-launched liferaft system.
1. Davit Arm Weakness
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Signs: Bending, excessive movement, or cracks.
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Solution: Reinforce or replace structural components.
2. Winch Malfunctions
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Signs: Difficulty in lifting or lowering, erratic operation.
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Solution: Lubricate, adjust, or replace winch components.
3. Cable and Hook Wear
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Signs: Frayed cables, worn-out hooks.
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Solution: Replace damaged cables and inspect the hook mechanism.
4. Hydraulic or Electrical Failures
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Signs: Loss of power, leaks, or erratic performance.
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Solution: Check and repair hydraulic or electrical components.
Post-Testing Documentation and Compliance
After weight testing, proper documentation must be maintained for regulatory compliance and future reference.
What Should Be Recorded?
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Date and location of the test.
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Test weight used (matching liferaft capacity).
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Observations and test results.
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Any issues detected and corrective actions taken.
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Certification or approval from the responsible authority.
Proper documentation ensures compliance with SOLAS, IMO, and classification society requirements.
Best Practices for Maintaining a Davit-Launched Liferaft
Regular maintenance helps keep the liferaft and davit system in optimal condition.
Routine Maintenance Checklist:
✅ Inspect the davit arm and structure for rust or damage.
✅ Check the winch and brake system for proper operation.
✅ Ensure the release hook mechanism is functional.
✅ Test the inflation system to confirm readiness.
✅ Lubricate moving parts to prevent corrosion.
✅ Perform load tests periodically as per regulations.
By following these best practices, ships and offshore facilities can ensure their liferafts are fully operational in emergencies.
Weight testing a davit-launched liferaft is a crucial safety procedure that ensures the liferaft can handle its full load during deployment. Conducted at least every five years, weight testing helps to identify structural weaknesses, comply with international maritime regulations, and improve crew safety.
By following proper testing procedures, addressing detected issues, and maintaining detailed records, ships can enhance their emergency preparedness and ensure the safety of everyone on board.