Iranian Classification Society Rules

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Section 3 Surveys


303. Special Survey

In application to 303. 5 (2) of the Rules, representative gaugings mean the requirements specified in Table 2.1 as follows.

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1. Surface type units

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Table 2.1 Minimum requirements for Thickness Measurements at Special Survey


Special Survey No. 1

Special Survey No. 2

Special Survey No. 3

Special Survey No. 4 and Subsequent

1. Suspect areas throughout the unit

1.Suspect areas throughout the unit

2.One transverse section of deck plating in way of the moon pool opening within the amidships 0.5 Ã , togeth- er with internals in way as deemed necessary by the Surveyor. Where unit is configured with side ballast tanks, the plating and in- ternals of the side ballast tanks are also to be gauged in way of the transverse section chosen.


3.Moon pool boundary bulk- head plating

1. Suspect areas throughout the unit

2. Two transverse sections of deck, bottom and side plat- ing in way of moon pool and one hatch opening within the amidships 0.5 Ã , together with internals in way as deemed necessary by the Surveyor. Where unit is configured with side ballast tanks, the plating and internals of the side ballast tanks are also to be gauged in way of the trans- verse sections chosen, Remaining internals in the side ballast tanks are to be gauged as deemed necessary by the Surveyor.


3. Moon pool boundary bulk- head plating

4. Internals in forepeak tank as deemed necessary by the Surveyor

1. Suspect areas throughout the unit

2. A minimum of three trans- verse sections of deck, bot- tom, side and longitudinal bulkhead plating in way of the moon pool and other areas within amidships 0.5 Ã , together with internals in way as deemed neces- sary by the Surveyor. Where unit is configured with side ballast tans, the plating and internals of the side ballast tanks are also to be gauged in way of the transverse sections chosen. Remaining internals in the side ballast tanks are to be gauged as deemed neces- sary by the Surveyor.

3. Moon pool boundary bulk- head plating

4. Internals in forepeak and afterpeak tanks as deemed

necessary by the Surveyor

5. Lowest strake of all trans- verse bulkheads in hold spaces. Remaining bulkhead plating are to be gauged as deemed necessary by the Surveyor.

6. All wind and water stakes, port and starboard, full length

7. All exposed main deck

plating full length and all exposed first-tier super- structure deck plating(poop, bridge and forecastle decks)

8. All keel plates full length. Also, additional bottom

plates in way of cofferdams

and machinery spaces

9. Duck keel and/or pipe tun- nel plating and internals as deemed necessary by the Surveyor

(NOTES)

1) Thickness measurement locations are to be selected to provide the best representative sampling of areas like- ly to be most exposed to corrosion, considering ballast history and arrangement and condition of protective coatings.

2) Thickness measurements may be specially considered by the Surveyor if the hard protective coating is in GOOD condition.

3) The Surveyor may extend the thickness measurements as deemed necessary. When thickness measurements indicate substantial corrosion, the extent of thickness measurements is to be increased to determine areas of substantial corrosion.

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2. Self-elevating units

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Table 2.1 Minimum requirements for Thickness Measurements at Special Survey (continued)


Special Survey No. 1

Special Survey No. 2

Special Survey No. 3

Special Survey No. 4 and Subsequent

1.Suspect areas throughout the unit

1. Suspect areas throughout the unit

2. Legs in way of splash zone5)

3. Primary structural mem- bers4) where wastage is evident or suspect


4. Representative thickness measurements of upper hull deck and bottom plat- ing and internal of one pre- load tank

1. Suspect areas throughout the unit

2. Leg well structure


3. Representative thickness measurements, throughout, of special portions of structural members and pri- mary structural members4)

4. Representative thickness measurements of deck, bot- tom and side shell plating of hull and mat


5. Representative thickness measurements of upper hull deck and bottom plating and internals of at least two pre-load tanks

1. Suspect areas throughout the unit

2. Leg well structure


3. All special portions of structural members and primary structural mem- bers4)


4. Representative thickness measurements of deck, bottom and side shell plat- ing of hull and mat

5. Substructure of derrick as deemed necessary by the Surveyor

6. Representative thickness measurements of upper hull deck and bottom plat- ing and internals of all pre- load tanks

(NOTES)

1) Thickness measurement locations are to be selected to provide the best representative sampling of areas like- ly to be most exposed to corrosion, considering ballast history and arrangement and condition of protective coatings.

2) Thickness measurements may be specially considered by the Surveyor if the hard protective coating is in GOOD condition.

3) The Surveyor may extend the thickness measurements as deemed necessary. When thickness measurements indicate substantial corrosion, the extent of thickness measurements is to be increased to determine areas of substantial corrosion.

4) Categories of structural members(primary structural members, secondary structural members and special por- tions of structural members) are defined in Ch 3, 1002. of the Rules.

5) Splash zone is to be considered as the structural area that has been periodically in and out of the water when the unit was at its operating depth, most of the time during the past five-year period. Based on op- erational record of the unit, additional zones may also be gauged.

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3. Column-stabilized units

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Table 2.1 Minimum requirements for Thickness Measurements at Special Survey (continued)



Special Survey No. 1


Special Survey No. 2


Special Survey No. 3


Special Survey No. 4 and Subsequent

1. Suspect areas throughout the unit


2. Columns and bracings where wastage is evident or suspect in splash zone5)

1. Suspect areas throughout the unit


2. Representative thickness measurements of columns and bracings in splash zone5) together with in- ternals in way as deemed necessary by the Surveyor


3. Special portions of structural members and primary structural mem- bers4) where wastage is evident or suspect

1. Suspect areas throughout the unit


2. One transverse section girth of each two columns and two bracings in splash zone5) together with in- ternals in way as deemed necessary by the Surveyor


3. Representative thickness measurements, throughout, of special portions of structural members and primary structural mem- bers4)


4. Chain locker internals as deemed necessary by the Surveyor


5. Lower hulls in way of mooring lines where was- tage is evident or suspect


6. One transverse section girth of each lower hull between one set of col- umns

1. Suspect areas throughout the unit


2. One transverse section girth of each one-half of the columns and two brac- ings in splash zone5) to- gether with internals in way as deemed necessary by the Surveyor(i.e., gauge half of the unit's columns and bracings in splash

zone5))


3. All special portions of structural members and primary structural mem- bers4)


4. Chain locker internals as deemed necessary by the Surveyor


5. Lower hulls in way of mooring lines where was- tage is evident or suspect


6. One transverse section girth of each lower hull between one set of col- umns


7. Representative thickness measurements of sub- structure of derrick

(NOTES)

1) Thickness measurement locations are to be selected to provide the best representative sampling of areas like- ly to be most exposed to corrosion, considering ballast history and arrangement and condition of protective coatings.

2) Thickness measurements may be specially considered by the Surveyor if the hard protective coating is in GOOD condition.

3) The Surveyor may extend the thickness measurements as deemed necessary. When thickness measurements indicate substantial corrosion, the extent of thickness measurements is to be increased to determine areas of substantial corrosion.

4) Categories of structural members(primary structural members, secondary structural members and special por- tions of structural members) are defined in Ch 3, 1002. of the Rules.

5) Splash zone is to be considered as the structural area that has been periodically in and out of the water when the unit was at its operating depth, most of the time during the past five-year period. Based on op- erational record of the unit, additional zones may also be gauged.


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ANNEX 1 DRILLING SYSTEMS

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