Answer MEP Question 18

Q.  List the  maintenance  routines  you  plan  to  carry  out  on  the  deck  hydraulic cranes, winches and mooring machinery before  arrival  port  after a long voyage,  considering the fact  that  cargo  operation is solely  dependent  on  the  proper  functioning  of the crane  and

winches.

-  Routine  inspection  and  maintenance  of  the  cranes (and  grabs,  if  fitted)  should  be  

carried  out according  to  the  manufacturer's maintenance  schedule  and  this should  be  

incorporated  into  the ship's planned maintenance system.

After long  Voyage

- Usually, the cranes are  not used during voyages  and hence after a long voyage,  it is vital to 

check the following aspects to ensure the gear is in good working condition.

Wires

-  Wires should be lubricated with the correct wire rope lubricant.  The  lubricant  

serves  two purposes -  to Lubricate  internally and externally  and to protect against  corrosion.

- Grease should  not  be  used.  Wire strands move against one another as the wire is tensioned and as it passes over sheaves.  The wire rope lubricant will penetrate into the core of the wire, whereas grease will sit on the surface of the wire and either be wished off or be contaminated with cargo dust and form a thick layer on the surface of the wire.

-  Wires should be regularly inspected for any damage. The wire may be damaged during cargo operations,  in particular, due to chafing against the hatch coaming.

-  Damaged   crane   wires   should   be  assessed   for  replacement  in accordance with manufacturer’s guidance or in  accordance  With ISO4309- Cranes-wire rope— Code of practice

Hydraulic Oil

-  The majority of cranes onboard ships are of the electrohydraulic type.  lt is important that the hydraulic oil is maintained in good condition.  In  addition  to regularly checking oil levels, filters should  be regularly inspected.  Filters often have indicators to show when they need cleaning and may have a magnet fitted, which should be inspected for any significant build-up of ferrous debris.

- One of the biggest causes of failures of hydraulic systems is dirty oil. Although hydraulic oil 

may look clean, particles in the oil that cannot  be seen by eye can cause control  valves to jam 

and will also cause wear of components.

- Water in the oil can cause corrosion and if the oil emulsifies this can lead to sluggish operation. Routine oil analysis should  be carried out  to ensure that  the oil is in a 

satisfactory condition and ideally, this should include a particle count.

Oil cooler; It is important that the oil cooler is regularly inspected and cleaned, particularly if the cranes are being operated in high ambient air temperature may need cleaning move frequently if the ship is regularly loading and discharging dusty cargoes.

- A dirty oil cooler may result in the crane cutting out if the high temperature limit is reached, 

which could lead to performance claims if the cranes are repeatedly stopping.

Brakes and safe devices

- The brakes on the cranes should be regularly inspected and their conditioñ recorded. Brakes often have indicators to show the correct brake tension but linings should be checked to ensure they are of adequate thickness and are not contaminated with oil.

-  Disk brakes are usually checked by measuring the clearance, and this should be recorded in the maintenance records.

- Limit switches should be regularly checked to ensure that they are operating correctly. The lower limit switch for the jib usually has a key-operated by-pass switch, used while stowing the jib.

- The jib should only be operated below its lower limits when it is being stowed. Operating  the 

jib below its lower limit, while there is the load on the hook, can lead to failure of the jib or the 

the luffing wire coming off its drum.

- Ensure  that  covers  on  limit  switches  are  properly  fitted  and  waterproof.  If  limit  

switches  and controls are not functioning  correctly,  this can result  in damage  to the crane 

and/or risk of injury to personnel.

- Operating conditions test - Deck cranes can be subject to demanding operating conditions, but the reliability of the cranes and the avoidance of costly and time-consuming breakdowns rely on the cranes being properly maintained.

Structural  maintenance 

- Check the base structure of the vessel for loosening foundation bolts and cracks in the structure. When the crane is operating  at its maximum load, the base structure undergoes 

heavy Stresses.

- The base structure  contains the rotational parts involving sheaves, bearings and slew rings 

etc.

They should be timely inspected to determine any wear on the parts. All these moving parts and equipment must be lubricated correctly rising the appropriate lubricant.

- Lifting Hook — This should be visually inspected to check for any possible cracks or damage. 

The self-locking mechanism if provided should be in good working condition.

- It is better to do an NDT spray test to ascertain the cracks.

- Electrical checks-As the panel for the crane is situated in the open deck, 

is usually prone to the effects of weather. Hence, the panels are opened after proper isolation and the terminals are checked for proper connection.

- Leads are removed and retightened.

- A proper insulation test on the motor is done and all required maintenance for the motor is done.