Everything You Ever Wanted To Know About Crankcase Inspection on a Ship

There are several important factors that need to be taken care of for efficient running of the main engine on the ship, and one of them is the crankcase of the ship’s engine. The crankcase is one such part of the main engine which contains the most sensitive components of the main engine. Before doing crankcase inspection, are you confused as to what safety rules that are need to be followed or ever wondered what you should check and what not? If yes, then you have come to the right place. In this article we will learn the most important points that need to be considered for efficient working of the crankcase of the main engine. Learn the important checks on crankcase and what all things need to be included in crankcase inspection on a ship.

Checks Required and Done On board on Crankcase Lubricating Oil

The crankcase lubricating oil needs to be maintained in good condition for efficient running of the main engine. If not maintained and checked periodically, the crankcase lubricating oil can damage the bearings and other parts of the engine which can incur heavy loss and wastage of time in maintenance. Moreover if the damage is more, the ship might need to go off charter which is not acceptable in shipping activities.

Weekly Checks on Crankcase

In weekly test of crankcase, lubricating oil water test should be done. This is to ascertain that there is no leakage in the crankcase and it’s in fine condition. If water content is below 2 % of the total volume then it is acceptable and can be reduced with the help of purification.


However, if it is above 2% then investigation needs to be made if there is any leakage of water inside the crankcase. In case of any leakage, the cracks are to be checks and fixed and the causes of water ingress is to be found. Once this is done the oil in the crankcase has to be replaced completely.

Other checks also done during weekly checks are to ascertain TBN and viscosity of the oil. The crankcase must be topped up or change of oil needs to be done as per manufacturer’s recommendation.

Once every three months the oil has to be sent for laboratory analysis i.e spectrography analysis to ascertain that the amount of wear and fine metal particles are within acceptable limit. In case if it is off limit, the laboratory analysis report will recommend procedure or precautions to be taken to tackle the situation.

Crankcase Inspection in large Slow Speed Engines

The crankcase inspection is done every month whenever the ship is in port and there is sufficient time for inspection. Thorough inspection is required during this to analyze the condition inside and damage to the bearings.

Before inspection following procedures has to be followed

  • Permission has to be taken before reaching port to make sure that the authority is not having any problem with this. This is called Immobilization permission of the main engine.
  • After the permission is received the checklist has to be filled.
  • Safety issues have to be discussed with the people taking part in the inspection.
  • When the engine is in “stopped” condition, the lubricating oil pump and cross-head oil pump have to be stopped and the breaker taken out so that it doesn’t start on its own or by any other person by mistake.
  • Proper sign and placards to be displayed regarding men at work.
  • Since engine crankcase is an enclosed space, an enclosed space entry checklist is also to be filled.
  • After stopping the engine and the pumps the crankcase doors have to be opened and sufficient time is to be given to cool and ventilate the space as the temperature inside is very hot and deprived of air.
  • After the cooling and ventilating the space, the person entering the space should be with proper personnel protective equipments like boiler suit, safety harness, and anti slipping pads for shoes.
  • Make sure there are no tools, pen etc in your pockets which might drop inside and cause damage to bearing and machinery parts
  • Before entering, the person has to be detailed as what needs be checked inside. Special attention is also given if any other issue is specified by technical department or any major problem found on other ships.

Inside Crankcase Following Checks are to be Made

1.     Check the overall quality of oil whether it is clean or dirty with carbon particles.

2.     Check for any distinguished smell, if found, this could be because of bacterial contamination of oil. The smell is generally of rotten eggs.

3.    Check for any metal particles near the grating in the crankcase.

4.   Check the condition and damage to the gratings.

5.    Check the slip marks on the web; they should be in the same line. If slip is found then report is to be made to the company and classification society regarding this.

6.    Check for any bluish dark patches, this indicates that hot spots are caused by friction of insufficient lubrication.

7.    Check cross head for any damages.

8.    Check cross head guides for damages and marks.

9.       Check the bed plate for any welding cracks etc.

10.   Check any metal seen near the bearings coming out due to wiping.

11.   Check for piping and any loose connections between them.

12.   Check the locking wires and locking washers on bolts of stuffing box.

13.   Make any other checks specified by technical department.

14.   Before coming out make sure there is nothing left inside.

Do you have info to share with us ? Suggest a correction

Subscribe To Our Newsletters

By subscribing, you agree to our Privacy Policy and may receive occasional deal communications; you can unsubscribe anytime.

Web Stories


  1. This text is comprehensive but NOT fully correct:

    – NO request to Immobilization required if crankcase will be open for inspection only. Immobilization – means overhauling of Main Engine
    when it is out of operation long time.

    – crankcase is NOT a tank, so it should not be considered as Enclosed space. because the condition of the air inside engine is NOT critical item – there is no problems as inspection doors are big enough and open during inspection.

    So, what for Check List for entrance into Enclosed Space required ???

  2. I am not sure about the checklist, but some port requirements adds immobilization certificate to be taken by ship authority for security reason

  3. vlasem, I really hope you are not an engineer serving on a ship at the moment.
    The crankcase is an enclosed space (an enclosed space does NOT have to be a tank), you do need to inform the Harbour master, and an inspection does dissable the engine.
    This is all basic marine engineering you should have learned as a cadet.

  4. Yes …Paper works…> 1. Immobilization 2. risk assessment form 3. safety meeting 4. enclosed space entry check list

  5. Vlasem, if you said that in an MCA oral exam you would be out the door without your feet touching the floor.

  6. please mr.mohit only sharing his knowlege,and in any engine room or in engineering nobody can say that he is a master in all.so only read to mr .mohit and what you want,not to aruge,just do the best.

  7. The topic is very well explained by Mr Mohit. One thing which can be added is taking clearances as part of regular checks. Gas checks, proper communications, rescue procedures in case of mishappening are important before making an entry.

  8. Good to read this conversation….thanks to u all..as a engine cadet what i know about enclosed space is where is no proper ventilation and that place can be a any danger for people.according this,my cabin also can be a enclosed space when there is no ventilation.i think crankcase should be enclosed space coz there may have oxygen deficiency…


  9. First thanks for the article it was really helpful.
    The Crank case is an inclosed space. “A confined space is a place which is substantially enclosed (though not always entirely), and where serious injury can occur from hazardous substances or conditions within the space or nearby (e.g. lack of oxygen).” This if from the UK government web sight, I think all of that applies to a crank case.


  10. What if cracks are found in the engine bed plate during crankcase inspection, how to rectify the cracks?

  11. @Paritosh: The best thing is to call the maker/shore technicians for the repairs. The best thing onboard crew can do is keep checking the tightness of the holding down bolts around that area. Any hot work (welding) should be avoided as it will further elevate the stress levels. If the crack is minor, wait for the shore repair, if the crack is major and cannot be ignored, better to drill and tap the end (the problem here is to find the tip of the crack).

  12. hello sir….i need a brief description
    about possible major defects that can be found in crankshaft during inspection???

  13. I would like to add 1 thing, the crankcase relief valve should also b checked. It should b pressed manually to ensure its not stuck and the o ring tht seals the valve should also be checked.

  14. Which part of the crankshaft of a modern large two stroke diesel engine is most likely to be the origin point for crack initiation during service and therefore needs the greatest attention during maintenance inspection?

  15. @Vishal Pil – Usually, those area which joined, holed etc after the forging of different parts. E.g. lubrication hole, looking pin etc. Also, fillet of the crankpin is an important area of inspection as it is under rotary and cyclic bending.

Leave a Reply

Your email address will not be published. Required fields are marked *