Davit is a system used to lower a lifeboat to the onboard level in case of an emergency. This system contains falls made of wire that are used to lower the lifeboat into the water when needed. Basically, davit is a single mechanical arm with a pulley that can be used for raising and lowering spare parts onto a lifeboat. International maritime organization (IMO) controls the maintenance and operation of davit or in a simple language, the operation and maintenance of davit system is under the jurisdiction of IMO and the regulations are imposed by the coast guard of a country. Before going into a detailed discussion of lifeboat davit testing, it is essential to understand about the basic parts of lifeboat davits.
- Basic Parts of Davit System
Gripes: Gripes are the ropes that are used to hold the lifeboat in a fixed position while underway.
Lifeboat: These can be open, enclosed or partially closed.
Tricing pendant: These lines are used to pull the lifeboat over the embarkation deck initially to connect the frapping lines.
Frapping lines: All davits except freefall and fixed davits contain these lines. These lines are used to pull the lifeboat over the embarkation deck along with tricing pendant to be loaded.
In last few years maritime industry has suffered a large number of accidents with lifeboats in which crew were injured seriously when it was participating in inspection. It was noticed that most of the accidents of lifeboats fall under following categories:
- Inadequate maintenance of davits and lifeboat equipments.
- Communication failure
- Unplanned operation of on-load release mechanism.
- Failure of on-load release mechanism.
- Lack of awareness with lifeboat equipments, davit and related control.
- Unsafe practices during inspection and lifeboat drills.
- Because of design fault.
In response to these issues, the IMO has made guidelines regarding the maintenance, safe servicing and drilling of lifeboats. In order to obey IMO SOLAR regulations, all the vessels are required to perform proof load testing of the launching appliances as well as on-load release mechanism of their lifeboats at the intervals not exceeding 5 years. Various periodic examinations or testing needed to avoid frequent accidents of lifeboats are as follows:
- Lifeboat Load Testing
Lifeboat load testing and lifeboat davit testing can be done by using water bags especially designed for this purpose. Load testing can be done by using water bags of 375 kg capacity. For load testing these bags are arranged inside the vessel to imitate passenger loading. Water can be accurately metered into these water bags by using certified volumetrically calibrated water meters. For proof load testing of lifeboat davit systems, a large number of water bags ranging from 2 to 12 metric tons are available in the market these days. Using water meters or load cells or both, the required load test can be applied accurately to meet out the applicable regulations that are needed for proper lifeboat davit testing.
Water weight load testing system has been specifically designed to provide a simple and safe method of load testing of life saving appliances including davits. Since bags are light and easy to handle therefore water bag load testing method is the best method for davit testing. Gradual filling of water in the bags allows any problem to be identified easily and quickly before attaining the maximum load. Static testing of davit system can be achieved safely and efficiently using water bags. In addition, water bag lifeboat test allows uniform as well as gradual application of the load. Controlled loading and unloading of water weights makes this test to achieve a wide range of capacities in a minimum time during load test.
- The Essentials to be Ensured for Lifeboat Davit Testing
The following items should be examined carefully for satisfactory operation of davit system:
Davit structure should be checked properly with particular regard to corrosion, especially behind head.
- Misalignment, deformation and excessive free play of the sheaves should be tested carefully.
- Damage to wire and sheaves because of corrosion and kinks should be inspected carefully.
- Hydraulic system should be in proper working conditions.
- Working of all limit switches
- Have a careful look on the stored power system including a check on the capacity.
- Checking of fall wire for correct termination of ends.
- Examination of fall wire end for replacement of wire.
- Check the condition of remote control wires and pulley carefully.
If lifeboat launching appliances are not properly maintained, it may lead to serious accidents. Therefore proper maintenance and inspection of lifeboat appliances is essential. The periodic servicing and testing of lifeboat davits and winches should be done only by the approved workshops. In addition, rescue boats, lifeboats, fast rescue boats and their launching appliances should also be serviced properly. Moreover all the documents related to the yearly maintenance of lifeboat and launching appliances should be available on board. All tests needed for checking the fault in design and operation of life saving appliances should be done rigorously and should comply with the guidelines developed by maritime and coastguard agency. This will help you to identify any fault in the design at an early stage.Share