Marine Engineering Study Materials

There are so many machinery and personnel accidents reported from marine vessels due to the failure of cranes on-board merchant ships in marine industry. The most common causes were malfunction of safety trips and cut outs, deterioration of wire ropes, badly worn out brake lining, etc. Maintenance of cranes, especially engine room cranes are totally neglected in most of the ships. For avoiding such accidents regular maintenance schedule must be set up for all the cranes working in marine vessels. Also cranes should be tested and certified by a shore based competent authority.

Any one of the marine engineer on-board ship along with electrical officer must be responsible for the maintenance and records for the crane. Following safety trips or cut outs and parts to be periodically inspected.

1. Lifting limit switch
2. Lowering limit switch
3. Forward travel limit switch
4. Aft travel limit switch
5. Port travel limit switch
6. Starboard travel limit switch
7. Limit switches to be tested electrically and mechanically.
8. Most neglected part is the gearing. Make sure that lube oil present in sufficient quantity inside the gear system. Drain completely and replace whole lube oil once in a year.
9. Brakes are very important as cranes are concerned. In case of power failure, brakes prevent load on hook to come down because of gravity. Brake lining to be checked for wear and must be within allowable limit.
10. All travelling tracks must be cleaned and greased with proper compounds.
11. Wire rope conditions to be checked for proper strength and no strands to be broken. Wire to be coated with grease compounds.
12. Condition of the shafts and pulley to be monitored and greased.
13. Hook must be free to rotate, to be checked for any cracks by work hardening. Safety latch to be functioning properly.
14. Check condition of drum where wire rope is wound.
15. Emergency stop location and operation for crane to be familiar for all ship staffs.

Since most of the ships are sailing in international ports, it is advisable to get the cranes certified from an international authority such as Lloyds or ABS. Also it is recommended to carry out load test once in 5 years.

All the engineers on-board must be familiar with the operation of crane. All the electrical contacts must be checked periodically. Maintain a history of job performed and is entered in the Planned Maintenance System (PMS). Inspection requirement and certification of engine room crane or any lifting gear is based on requirement for dock worker safety, health and welfare regulation 1990. As per regulation, a register to be maintained on board ships. The register and the certificate for the crane shall be produced on demand from authorities.

The documents of crane to be carried on board ships are:

1. Crane manual
2. Initial load test certificate
3. Periodic test certificate (5 years)
4. Lifting gear register
5. Annual survey report

Crane is tested to 1.5 times safe working load (SWL), by using a dynamo-meter. One end of the dynamo-meter is connected to the crane hook while other end is connected to a strong point in ship structure. The load can be read from readings shown. Separate test certificate is required for wire slings that are used along with crane. Annual inspection is carried out by ship staff and is recorded in the register.

See Also: Working Aloft Permit

See Also: MEO Class Examination