1 General
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.744(18) Guidelines on the Enhanced Programme of Inspections During Surveys for Bulk Carriers and Oil Tankers (Adopted on 4 November 1993) - Annex B - Guidelines on the Enhanced Programme of Inspection During Surveys for Oil Tankers - Part A - Guidelines on the Enhanced Programme of Inspections During Surveys of Double Hull Oil Tankers - 1 General

1 General

1.1 Application

  1.1.1 The Guidelines should apply to all self-propelled double hull oil tankers of 500 gross tonnage and above.

  1.1.2 The Guidelines should apply to surveys of hull structure and piping systems in way of cargo tanks, pump rooms, cofferdams, pipe tunnels, void spaces within the cargo area and all ballast tanks. The surveys should be carried out during the surveys prescribed by regulation I/10 of the 1974 SOLAS Convention, as amended.

  1.1.3 The Guidelines contain the extent of examination, thickness measurements and tank testing. The survey should be extended when substantial corrosion and/or structural defects are found and include additional close-up survey when necessary.

1.2 Definitions

  1.2.1 Double hull oil tanker is a ship which is constructed primarily for the carriage of oil in bulk, which have the cargo tanks protected by a double hull which extends for the entire length of the cargo area, consisting of double sides and double bottom spaces for the carriage of water ballast or void spaces.

  1.2.2 A ballast tank is a tank which is used solely for water ballast.

  1.2.3 Overall survey is a survey intended to report on the overall condition of the hull structure and determine the extent of additional close-up surveys.

  1.2.4 Close-up survey is a survey where the details of structural components are within the close visual inspection range of the surveyor, i.e. preferably within reach of hand.

  1.2.5 Transverse section includes all longitudinal members such as plating, longitudinals and girders at the deck, sides, bottom, inner bottom and longitudinal bulkheads.

  1.2.6 Representative tanks are those which are expected to reflect the condition of other tanks of similar type and service and with similar corrosion protection systems. When selecting representative tanks account should be taken of the service and repair history onboard and identifiable critical and/or suspect areas.

  1.2.7 Suspect areas are locations showing Substantial Corrosion and/or are considered by the surveyor to be prone to rapid wastage.

  1.2.8 Substantial corrosion is an extent of corrosion such that assessment of corrosion pattern indicates a wastage in excess of 75% of allowable margins, but within acceptable limits.

  1.2.9 Corrosion prevention system is normally considered either:

  • .1 a full hard coating, or

  • .2 a full hard coating supplemented by anodes.

Protective coating should usually be epoxy coating or equivalent. Other coating systems may be considered acceptable as alternatives provided that they are applied and maintained in compliance with the manufacturer's specification.

Where soft coatings have been applied, safe access should be provided for the surveyor to verify the effectiveness of the coating and to carry out an assessment of the condition of internal structures which may include spot removal of the coating. When safe access cannot be provided, the soft coating should be removed.

  1.2.10 Coating condition is defined as follows:

GOOD condition with only minor spot rusting,
FAIR condition with local breakdown of coating at edges of stiffeners and weld connections and/or light rusting over 20% or more of areas under consideration, but less than as defined for POOR condition,
POOR condition with general breakdown of coating over 20% or more of areas or hard scale at 10% or more of areas under consideration.

  1.2.11 Critical structural areas are locations which have been identified from calculations to require monitoring or from the service history of the subject ship or from similar or sister ships to be sensitive to cracking, buckling or corrosion which would impair the structural integrity of the ship.

  1.2.12 Cargo area is an area as defined in regulation II-2/3.6 of the 1974 SOLAS Convention, as amended.

  1.2.13 Intermediate survey is a survey carried out either at the second or the third annual survey or between these surveys.

  1.2.14 A prompt and thorough repair is a permanent repair completed at the time of survey to the satisfaction of the Surveyor, therein removing the need for the imposition of any associated condition of classification or recommendation.

  1.2.15 Specially considered means sufficient close-up inspection and thickness measurements are taken to confirm the actual average condition of the structure under coating.

1.3 Repairs

  1.3.1 Any damage in association with wastage over the allowable limits (including buckling, grooving, detachment or fracture), or extensive areas of wastage over the allowable limits, which affects or, in the opinion of the Administration, will affect the ship's structural, watertight or weathertight integrity, should be promptly and thoroughly (see 1.2.14) repaired. Areas to be considered include:

  • .1 bottom structure and bottom plating;

  • .2 side structure and side plating;

  • .3 deck structure and deck plating;

  • .4 inner bottom structure and inner bottom plating;

  • .5 inner side structure and inner side plating;

  • .6 longitudinal bulkhead(s) structure and longitudinal bulkhead(s) plating, where fitted;

  • .7 transverse watertight or oiltight bulkheads structure and transverse watertight or oiltight bulkheads plating;

  • .8 hatch covers or hatch coamings, where fitted; and

  • .9 items in paragraph 3.3.

Where adequate repair facilities are not available, the Administration may allow the ship to proceed directly to a repair facility. This may require discharging the cargo and/or temporary repairs for the intended voyage.

  1.3.2 Additionally, when a survey results in the identification of corrosion or structural defects, either of which, in the opinion of the Administration, will impair the ship's fitness for continued service, remedial measures should be implemented before the ship continues in service.

1.4 Surveyors

 For tankers of 20,000 tons deadweight and above, two surveyors should jointly carry out the first scheduled renewal survey after the tanker passes 10 years of age, and all subsequent renewal surveys and intermediate surveys. If the surveys are carried out by a recognized organization, the surveyors should be exclusively employed by such recognized organizations.

Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.