What do you need to know about vessel surveys in general

There were a lot of questions and queries, from different engineers, about vessel surveys and would like to clarify as much as I can about the type of surveys, their periodicity and requirements. Nonetheless, I am sure that I might unintentionally forget or omit something and for that I would beg for your understanding and thank you in the same time for your correction and any additional information related to this subject.

There are different types of surveys that takes place in a vessel lifetime and unfortunately, schools, colleges and universities doesn’t have a proper subject on the matter or doesn’t prepare an aspiring marine engineer for these type of experiences and activities, unless will attend a specific surveyor course. Everything is learned “on the field”, throughout engineer personal experience or with help of his/her senior officers.

The type of surveys are generally as follow:

    • Statutory surveys
    • New construction surveys
    • Existing ships survey
    • Damages, repairs and alterations
    • Existing ships – periodical surveys
    • Surveys for novel/complex systems, machinery and equipment

Statutory surveys

When given the authority to do so on behalf of national or international governments, the Classification Committee will act in accordance with national and international statutory safety and other requirements for passenger and cargo vessels.
In the event that it is given the authority to do so, the Classification Committee will also act in regard to National Safety and other standards that pertain to ships that are employed for offshore resource exploration and exploitation.

New construction surveys

Constructional plans and all necessary particulars relevant to the hull, equipment, and machinery, as detailed in the Rules, are to be submitted for approval prior to the commencement of any work when it is intended to build a ship for classification with a Classification Society. This must be done before any work is started. The proposals for any later alterations or additions to the scantlings, arrangements, or equipment shown on the authorized plans are also required to be submitted in writing and on plans for approval. These proposals can be made at any time after the plans have been accepted.

Example of new building in shipyard

Special tests or examinations before and during service may be necessary where the proposed construction of any part of the hull or machinery is of novel design, involves the use of unusual material, or where experience, in the opinion of the Classification Committee, has not sufficiently justified the principle or mode of application involved. A suitable notation may be used in these circumstances.

When a ship, upon completion, is not immediately commissioned but is laid-up for a period, the Classification Committee, upon application by the Owner, prior to the ship proceeding to sea, will direct an examination to be made by the Surveyors which may include a survey in dry-dock. If, as the result of such a survey, the hull and machinery be reported in all respects in accordance with applicable Rule requirements, the subsequent Special Survey and Complete Survey of the machinery will date from the time of such examination.

Existing ships survey

    • Classification of ships not built under survey – this refers to the requirements of the Classification Committee for the classification of ships which have not been built under the present Classification Society. Special consideration will be given to ships transferring class to actual Classification Society from another recognized Classification Society.
    • Reclassification – when reclassification or class reinstatement is desired for a ship for which the class previously assigned by actual Classification Society has been withdrawn or suspended, the Classification Committee will direct that a survey, appropriate to the age of the ship and the circumstances of the case, be carried out by the Surveyors. If, at such a survey, the ship be found or placed in a condition in accordance with the requirements of the Rules and Regulations, the Classification Committee will be prepared to consider reinstatement of the original class or the assignment of such other class as may be deemed necessary.
    • Unscheduled surveys – where the Classification Committee has concern about the condition of a ship and/or the equipment an unscheduled survey may be required at any time to determine the actual condition.

Damages, repairs and alterations

All repairs to hull, equipment and machinery which may be required in order that a ship may retain her class, are to be carried out to the satisfaction of the surveyors. When repairs are effected at a port, terminal or location where the services of a Surveyor to actual  Classification Society are not available, the repairs are to be surveyed by one of the surveyors at the earliest opportunity thereafter.

Vessel surveyor checking and marking rudder defects during dry docking

When, at any survey, the surveyors consider repairs to be immediately necessary, either as a result of damage, or wear and tear, they are to communicate their recommendations at once to the Owner, or his representative. When such recommendations are not complied with, immediate notification is to be given to the Classification Committee by the surveyors.

Where repairs are to be carried out by a riding crew during a voyage then these must be planned in advance. A complete repair procedure, including the extent of proposed repair and the need for Surveyor’s attendance during the voyage, is to be submitted reasonably in advance to the Surveyor for agreement. Failure to notify the Classification Society in advance of the repairs may result in the class of the ship being specially considered by the Classification Committee. Where emergency repairs are effected immediately due to an extreme emergency circumstance, the repairs should be documented in the ship’s log and submitted thereafter to the Classification Society for use in determining further survey requirements.

When, at any survey, it is found that any damage, defect or breakdown is of a nature that does not require immediate permanent repair, but is sufficiently serious to require rectification by a prescribed date in order to maintain class, a suitable condition of class is to be imposed by the surveyors and recommended to the Classification Committee for consideration.

Plans and particulars of any proposed alterations to the approved scantlings and arrangements of hull, equipment, or machinery are to be submitted for approval, and such alterations are to be carried out to the satisfaction of the surveyors.

Existing ships – periodical surveys

Annual Surveys are to be held on all ships within three months, before or after each anniversary of the completion, commissioning or Special Survey in accordance with the requirements of Periodical Survey Regulations. The date of the last Annual Survey will be recorded on the Class Direct website.

Intermediate Surveys are to be held on all ships instead of the second or third Annual Survey after completion, commissioning or Special Survey. The Intermediate Survey may be commenced at the second Annual Survey and progressed with completion at the third Annual Survey. The date of the last Intermediate Survey will be recorded on the Class Direct website. The concurrent crediting of items towards both Intermediate Survey and Special Survey is not permitted.

The Owner should notify the Classification Society whenever a ship can be examined in dry-dock or on a slipway. A minimum of two Bottom Surveys are to be held in each five-year special survey period and the maximum interval between successive bottom surveys is not to exceed three years. One of the two bottom surveys required in each five-year period is to coincide with the Special Survey. Consideration may be given in exceptional circumstances to an extension of the Bottom Survey, not exceeding three months, provided the interval between successive surveys does not exceed 36 months. A Bottom Survey is an examination of the outside of the ship’s bottom and related items, and is normally to be carried out with the ship in dry-dock. However, the Classification Committee may give consideration to alternate examination while the ship is afloat as an In-Water Survey, which however shall not be permitted for ships of 15 years of age and over. A bottom survey is considered to coincide with the special survey when held within the 15 months prior to the due date of the special survey.

Example of a vessel in dry dock for its special survey

Where the Special Survey of the hull is carried out on a Continuous Survey basis, the survey in Dry Dock may be held at any time within the five-year cycle. These Surveys become due at five-yearly intervals, the first one five years from the date of build or date of Special Survey for Classification as recorded in the Register Book, and thereafter five years from the date recorded for the previous Special Survey. Consideration may be given at the discretion of the Committee to any exceptional circumstances justifying an extension of the hull classification to a maximum of three months beyond the fifth year. If an extension is agreed the next period of hull classification will start from the due date of the Special Survey before the extension was granted. In this context ‘exceptional circumstances’ means unavailability of dry-docking facilities, repair facilities, essential materials, equipment or spare parts or delays incurred by action taken to avoid severe weather conditions.

Special Surveys may be commenced at the fourth Annual Survey after completion, commissioning, or previous Special Survey, and be progressed during the succeeding year with a view to completion by the due date of the Special Survey.  When Special Surveys are commenced prior to the fourth Annual Survey, the entire survey is to be completed within 15 months if such work is to be credited towards the Special Survey.

At the request of an Owner, it may be agreed that the Special Survey of the hull, for ships other than general dry cargo ships, bulk carriers, combination carriers, chemical tankers and oil tankers, be carried out on the Continuous Survey basis, all compartments of the hull being opened for survey and testing, in rotation, with an interval of five years between consecutive examinations of each part. In general, approximately one fifth of the Special Survey is to be completed each year and all the requirements of the particular hull Special Survey must be completed at the end of the five-year cycle. For ships more than 10 years of age, an examination of the ballast tanks is to be carried out twice in each five year cycle, i.e. once within the scope of the Intermediate Survey and once within the scope of the Continuous Survey. Ships which have satisfactorily completed the cycle will have a record entered in the Class Direct indicating the date of completion which will not be later than five years from the last assigned date of Complete Survey of the hull. The agreement for surveys to be carried out on Continuous Survey basis may be withdrawn at the discretion of the Classification Committee.

When, at the request of an Owner, it has been agreed by the Classification Committee that the Complete Survey of the machinery may be carried out on the Continuous Survey basis, the various items of machinery are to be opened for survey in rotation, as far as practicable, to ensure that the interval between consecutive examinations of each item will not exceed five years. In general, approximately one-fifth of the machinery is to be examined each year. If any examination during Continuous Survey reveals defects, further parts are to be opened up and examined as considered necessary by the Surveyor, and the defects are to be made good to his satisfaction.

Boiler survey in progress with attendance of an ABS surveyor

Upon application by an Owner, the Classification Committee may agree to an arrangement whereby, subject to certain conditions, some items of machinery may be examined by the Chief Engineer of the ship at ports where Classification Society is not represented, or, where practicable, at sea, followed by a limited confirmatory survey carried out at the next port of call where a surveyor is available. Particulars of this arrangement may be obtained from Classification Society. Where an approved planned maintenance scheme is in operation, the confirmatory surveys may be held at annual intervals, at which time the records will be checked and the operation of the scheme verified.

Where condition monitoring equipment is fitted, the Classification Committee, upon application by the Owner, will be prepared to amend applicable Periodical Survey requirements where details of the equipment are submitted and found satisfactory. Where machinery installations are accepted for this method of survey, it will be a requirement that an Annual Survey be held, at which time monitored records will be analyzed and the machinery examined under working conditions. An acceptable lubricating oil trend analysis programme may be required as part of the condition monitoring procedures.

Where any inert gas system is fitted for the protection of cargo tanks on board a ship intended for the carriage of oil or liquid chemicals in bulk, the system is to be surveyed annually.

Surveys for novel/complex systems, machinery and equipment

Where novel/complex systems, machinery and equipment have been accepted by Classification Society and for which existing survey requirements are not considered to be suitable and sufficient then appropriate survey requirements are to be derived as part of the design approval process. In deriving these requirements Classification Society will consider, but not be limited to, the following:

      • Plan appraisal submissions
      • Risk Assessment documentation where required by the Rules
      • Equipment manufacturer recommendations
      • Relevant recognised national or international standards


When the required reports, on completion of the survey of new or existing ships which have been submitted for classification, have been received from the surveyors and classification has been agreed, a Certificate of Classification may be issued by an authorized surveyor. After approval by the Classification Committee, a certificate of First Entry of Classification, signed by Classification Society Chairman or the Chairman of the Classification Committe, will be issued to Builders or Owners.

A Certificate of Class valid for five years subject to endorsement for Annual and Intermediate Surveys will also be issued to the Owners.

Classification Society surveyors are permitted to issue provisional (interim) certificates to enable a ship to proceed on her voyage (or to continue her service in the case of a fixed or tethered ship) provided that in their opinion it is in a fit and efficient condition. Such certificates will embody the surveyor’s recommendations for continuance of class, but in all cases are subject to confirmation by the Classification Committee.

On future posts will discuss about specific surveys (e.g boiler, screwshaft, hull and machineries etc.) where I will try try to explain in detail the requirements and necessary preparation prior surveyor attendance.

If you have any questions regarding above, please feel free to use our existing forum Seafarer’s World and will try to answer to all your queries.

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Source and Bibliography:

  • Lloyd Register
  • DNV
  • American Bureau of Shipping

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