What is Harmonised Survey System for Ships?

On February 3, 2000, International Maritime Organization (IMO) adopted a harmonised survey system for ships, in order to alleviate the problems caused by survey dates and intervals between surveys which do not coincide, covering international shipping regulations including the codes and conventions of these following institutions:

  • The International Convention on Load Lines (LL), 1966
  • The International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto –MARPOL 73/78
  • The International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code)
  • Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (BCH Code)
  • Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code).

Harmonised Survey System


1) A standard interval of one year between harmonised surveys for ships which could be based on any of the followings:

  • Initial survey – A complete inspection of all the items concerning the particular certificate before the ship is put into service to make sure they possess satisfactory conditions and are capable of carry out the service for which the ship is intended
  • Periodical survey – An official examination of the items relating to the particular certificate to ensure that they are meeting the requirements and are fit for the intended services
  • Renewal survey – As similar as the periodical survey but consequently results in issuing a new certificate
  • Intermediate survey – Inspection of specified items
  • Annual survey – General reviewing of the items concerned to the particular certificate to ascertain the fact that they have been observed maintained and remained fit for the service for which the ship is designated.
  • Additional survey – General or partial Inspection, according to the circumstances, made after a repair resulting from casualty probes or whenever there is an important repair or renewal made.

2) A maximum period of validity of one year and five years for all passenger ship certificates and cargo ship certificates respectively

3) Three months extension for cargo ship certificates on the harmonised survey system for ships and one month for short voyages. When the duration of a particular certificate is extended, the period of validity of new certificate begins from the expiry date of last certificate.

4) At least two inspections are required to be executed of the ship’s bottom in a five year period; maximum interval between the inspections has also been set at not more than thirty six months.

Harmonised Survey System

5) A substantive harmonised system for merchant marine which credits a combined cargo ship safety certificate to replace existing safety equipment, safety construction and safety radio certificates

6) No more unscheduled inspections for harmonised system of classification for ships, while annual surveys have been made mandatory.


Surveys, made in accordance with the harmonised survey system for ships, are purported to harmonize intervals between surveys of all legitimate certificates issued to all marine vessels. The harmonized system is presumed to facilitate all the troubles of periods between surveys so that any ship would not have to worry about going into the process of a survey schedule required by one convention right after having gone through the same thing concerned in connection with another instrument.


The Harmonised system of classification for ships is related to several certificates, depending upon the type of ships, including:

  • Passenger Ship Safety Certificate, including Record of Equipment
  • Cargo Ship Safety Construction Certificate
  • Cargo Ship Safety Equipment Certificate, including Record of Equipment
  • Cargo Ship Safety Radio Certificate, including Record of Equipment
  • Cargo Ship Safety Certificate, including Record of Equipment
  • International Load Lines Certificate
  • International Load Lines Exemption Certificate
  • International Oil Pollution Prevention Certificate
  • International Pollution Prevention Certificate for the Carriage of Noxious Liquid Substances in Bulk
  • International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk
  • International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk
  • Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk


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  1. You joined to ship as second engineer’
    You see vit system not working.
    What’s your actions?

  2. Very good for learners and professionals to get in touch with evolving new technology and latest up-date on IMO requirements.

  3. VIT is very important for Main Engine to keep the peak pressure of individual unit at required level in various engine load to achive greater combustion. By altering the fuel pump timing of MC engines this is achived, actually moving the pump barrel up or down. Now if the VIT system does not work, it will directly impact on the performance of the engine. You will get less power output at NCR form power you suppose to get at that point. Many calculation will change then. Your ships rpm, speed, power output, SFOC, all will deviate from trial value. Now if you think about taking some action regarding this then you need to start troubleshooting, This may take time. If system is down for prolong period you have to overhaul all unit VIT cylinders, clearing the pneumatic lines, cleaning control valves,filters related to this line then check the Current to Pressure (I/P) Converter. Hopefully your problem will be solved. If nothing can be done then last option in my opinion is to adjust the VIT rack according to the load. All these i write based on 11K98MC MAN B&W engine. However worse thing will happen if it malfunction, for example if VIT activated at low load then you will experiance peak pressure become maximum at only 50% MCR.

    1.3 The harmonized system, a diagrammatic arrangement of which is given in appendix 2, provides for:
    1.3.2 a scheme providing the necessary flexibility to execute each survey, with provision for: completion of the renewal survey within three months before the expiry date of the existing certificate with no loss of its period of validity;

    Question 1: word “its” in last paragraph is referred to Existing Valid Ship’s Certificate or New Ship’s Certificate that will be issued after renewal survey?
    Question 2: word “flexibility” could permit the Administration to issue a certificate with more than 5 years validity? i.e. : according to prepare a renewal inspection, 1 month before expiry date of Existing valid Certificate, is it permitted New Certificate be issued by validity of 5 years and 1 month (61 months)?

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