Surveys of Double Hull Oil Tankers – Hull

(c) Hatch covers and coamings

In addition to the requirements of the annual survey, the following items are to be surveyed.

(i) Checking of the satisfactory operation of all mechanically operated hatch covers is to be made, including:

(1) Stowage and securing in open condition;

(2) Proper fit and efficiency of sealing in closed condition; and

(3) Operational testing of hydraulic and power components, wires, chains and link drives.

(ii) Checking the effectiveness of sealing arrangements of all hatch covers by hose testing or equivalent.

(iii) Thickness measurement of the hatch cover and coaming plating and stiffeners is to be carried out as given in Table I 2-14, and the the thickness measurement of hatch cover and coaming plating in way of Substantial Corrosion is to be carried out as given in Table I 2-16.

(d) Extent of overall and close-up survey

(i) An overall survey of all tanks and spaces, excluding fuel oil, lube oil and fresh water tanks, is to be carried out at each special survey.

(ii) Each special survey is to include a close-up survey of sufficient extent to establish the condition of the shell frames and their end attachments in all cargo holds and salt water ballast tank s as indicated in Table I 2-14.

(e) Extent of thickness measurement

(i) The minimum requirements for thickness measurements at special survey are given in Table I 2 -15 and Table I 2-16.

(ii) Thickness measurement to determine both general and local levels of corrosion in the shell frames and their end attachments in all cargo holds and salt water ballast tanks is to be carried out.

Thickness measurement is also to be carried out to determine the corrosion levels on the transverse bulkhead plating. The thickness measurements may be dispensed with provided the Surveyor is satisfied by the close-up survey, that there is no structural diminution, and the protective coating where applied remains efficient.

(iii) The Surveyor may extend the thickness measurements as deemed necessary. When thickness measurements indicate Substantial Corrosion, the number of thickness measurements is to be increased to determine the extent of Substantial Corrosion as deemed necessary by the Surveyor.

(iv) Transverse sections are to be chosen where the largest reductions are suspected to occur or are revealed from deck plating measurements.

(f) Extent of tank testing

(i) All boundaries of salt water ballast tanks and deep tanks used for salt water ballast within the cargo length area are to be pressure tested. For fuel oil tanks, only representative tanks are t o be pressure tested.

(ii) The Surveyor may extend the tank testing as deemed necessary.

(iii) Tanks are to be tested with a head of liquid to the top of the air pipes for ballast tanks and deep tanks or the pressure corresponding to the maximum head that can be experienced in service for oil tanks.

2.13 Surveys of Double Hull Oil Tankers – Hull

These requirements 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 for the double hull oil tankers with ESP notation.

2.13.1 Annual survey (a) General

(i) The due range of annual survey is to be in accordance with the applicable requirements of 2.5.

2.13 Surveys of Double Hull Oil Tankers – Hull

(ii) The survey is to consist of an examination for the purpose of ensuring, as far as practicable, that the hull and piping are maintained in a satisfactory condition.

(b) Examination of the hull

(i) Examination of the hull plating and its closing appliances as far as can be seen.

(ii) Examination of watertight penetrations as far as practicable.

(c) Examination of weather decks

(i) Examination of cargo tank openings including gaskets, covers, coamings and flame screens.

(ii) Examination of cargo tanks pressure/vacuum valves and flame screens.

(iii) Examination of flame screens on vents to all bunker, oily ballast and oily slop tanks.

(iv) Examination of cargo, crude oil washing, bunker and vent piping systems, including vent masts and headers.

(d) Examination of cargo pump rooms and pipe tunnels

(i) Examination of all pump room bulkheads for signs of oil leakage or fractures and, in particular, the sealing arrangements of all penetrations of pump room bulkheads.

(ii) Examination of the condition of all piping systems.

(e) Examination of ballast tanks

(i) Examination of ballast tanks when required as a consequence of the results of the special survey and intermediate survey. When considered necessary by the Surveyor, thickness measurement is to be carried out and if the results of these thickness measurements indicate that Substantial Corrosion is found, additional thickness measurements are to be carried out as deemed necessary by the Surveyor.

(ii) Double hull oil tankers exceeding 15 years of age, all ballast tanks adjacent to (i.e. with a common plan boundary) a cargo tank with any means of heating are to be examined internally. Ballast tanks which were found, at the previous Intermediate or special survey, to have no Substantial Corrosion within the tank and which were found in compliance with either of the following conditions may be specially considered by the Society:

(1) coating in Good condition; or

(2) coating of the common boundary, including adjacent structures, in Good condition and the coating of the remaining parts of the tank in Fair condition.

2.13.2 Intermediate survey (a) General

(i) The due range of intermediate survey is to be in accordance with the applicable requirements of 2.6.

(ii) At each intermediate survey, in addition to the requirements of the annual surveys, the foll owing items are to be surveyed.

(iii) For double hull oil tankers exceeding 15 years of age, the requirements of the intermediate survey are to be to the same extent as the previous special survey as required in 2.1.5(a) and 2.13.3.

However, pressure testing of cargo and ballast tanks is not required unless deemed necessary by attending Surveyor.

(iv) In application of (iii) above, a survey in dry dock is to be part of the intermediate survey. The overall and close-up surveys and thickness measurements, as applicable, of the lower portions of the cargo tanks and water ballast tanks are to be surveyed in accordance with the applicable requirements for the intermediate surveys, if not already surveyed.

(v) For ships over 20 years of age after launching date, the applicable requirements specified in 2.6 are to be applied at the intermediate survey carried out within 3 months before or after the anniversary date from the previous special survey.

(b) For weather decks, an examination as far as applicable of:

2.13 Surveys of Double Hull Oil Tankers – Hull

(i) Cargo, crude oil washing, bunker, ballast, steam and vent piping systems as well as vent masts and headers is to be carried out.

(ii) If upon examination there is any doubt as to the condition of the piping, the piping may be required to be pressure tested, thickness measured or both.

(c) Extent of overall survey and close-up survey

The extent of overall survey and close-up survey for intermediate survey is to be in accordance with the requirements of Table I 2-17.

(d) Extent of Thickness Measurements

(i) The extent of thickness measurements is also given in Table I 2-17.

(ii) The minimum requirements for thickness measurements at the intermediate survey are areas found to be Suspect Areas at the previous special survey.

(iii) Where Substantial Corrosion is found, the extent of the thickness measurements according to Table I 2-17 is to be increased in accordance with the requirements of Table I 2-20. These extended thickness measurements are to be carried out before the survey is credited as completed. Suspect Areas identified at previous special surveys are to be examined.

(iv) Areas of Substantial Corrosion identified at previous special or intermediate survey are to have thickness measurements taken.

(e) Double hull oil Tankers exceeding 15 years of age

(i) The requirements of the intermediate survey are to be to the same extent as the previous special survey as required in 2.13.3 and 2.1.5. However, pressure testing of cargo and ballast tanks is not required unless deemed necessary by the attending Surveyor.

(ii) A survey in dry dock is to be part of the intermediate survey. The overall and close -up surveys and thickness measurements, as applicable, of the lower portions of the cargo tanks and water ballast tanks are to be surveyed in accordance with the applicable requirements for intermediate surveys, if not already surveyed.

2.13.3 Special survey (a) General

(i) The due range of Special Survey is to be in accordance with the applicable requirements of 2.7.

(ii) The special survey is to include, in addition to the requirements of the intermediate survey, examination, tests and checks of sufficient extent to ensure that the hull and related piping is in a satisfactory condition.

(iii) All cargo tanks, all salt water ballast tanks, pump rooms, pipe tunnels, cofferdams and void spaces bounding cargo tanks, decks and outer hull are to be examined. This examination is to be supplemented by thickness measurement and pressure testing as deemed necessary, to ensure that the structural integrity remains effective. The examination is to be sufficient to discover Substantial Corrosion, significant deformation, fractures, damages or other structural deterioration.

(iv) Cargo piping on deck, including crude oil washing (COW) piping, and all piping systems within the above tanks and spaces are to be examined and operationally tested to working pressure to attending Surveyor's satisfaction to ensure that tightness and condition remain satisfactory. Where provided, special attention is to be given to any ballast piping in cargo tanks and cargo piping in ballast tanks and void spaces, and Surveyors are to be advised on all occasions when this piping, including valves and fittings are opened during repair periods and can be examined internally.

(v) A survey in dry dock is to be a part of the special survey.

(b) Tank protection

(i) Where provided, the condition of corrosion prevention of cargo tanks is to be examined.

(ii) For tanks used for salt water ballast, where a protective coating is found in Poor condition and it is not renewed, where a soft or semi-hard coating has been applied, or where a protective coating was