Rules for Ships, January 2015

Pt.7 Ch.1 Sec.4 Renewal surveys extent main class Page 84

DET NORSKE VERITAS AS

Table 21 Close-up examination, double hull oil tankers and double hull chemical tankers

Area Renewal survey no. 1

Age 5 years

Renewal survey no. 2

Age 5 - 10 years

Renewal survey no. 3 8)

Age 10 - 15 years

Renewal survey no. 4 8)

and subsequentAge > 15 years

1 Deck transverse including adjacent deck structural members5).

One - in a cargo tank.

One - in each of two cargo tanks.

All - in a cargo tank. All - in a cargo tank.

One - in each remaining cargo tank.

One - in each remaining cargo tank.

2a Transverse double hull web frames 1), including adjacent structural members.

One - in a ballast tank within the cargo area.

All - in a ballast tank within the cargo area.

All - in all ballast tanks.

All - in all ballast tanks.

One - knuckle area 3) and the upper part (approximately 3 - 5 metres) in each remaining ballast tank.

2b Transverses web frames 4), including adjacent structural members.

All - in a cargo tank. All - in a cargo tank.

One - in each remaining cargo tank.

One - in each remaining cargo tank.

3 Transverse bulkheads including girder system and adjacent structural members.

One - in a ballast tank2).

One - in each ballast tank2).

All - in all ballast tanks.

All - in all ballast tanks.

One, lower part 6)

- in a cargo wing tank.

One, lower part 6)

- in a cargo wing tank.

All - in all cargo tanks.

All - in all cargo tanks.

One, lower part 6)

- in a cargo centre tank 7).

One, lower part 6)

- in two cargo centre tanks 7).

4 Double bottom structures

As covered by item 2a and 2b.

As covered by item 2a and 2b.

As covered by item 2a and 2b.

As covered by item 2a and 2b.

Notes:

1) Transverse double hull web frame means vertical web in double side tank, hopper web in hopper tank, floor in double bottom tank and deck transverse in double deck tank (where fitted).

When applicable to forepeak and aftpeak tanks this means a complete transverse web frame ring.

1) Including double bottom tank, double side tank and double deck tank as applicable if these are separate tanks.

2) The knuckle area is the area of the web frame around the connections of the slope hopper plating to the inner hull bulkhead and the inner bottom plating, up to 2 metres from the corners both on the bulkhead and the double bottom.

3) Transverses web frame means deck transverse, longitudinal bulkhead vertical girder and cross ties where fitted.

4) Including external structure on deck in way of the tank, where applicable.

5) Including internal structure of lower stool, where fitted.

6) Where no centre cargo tanks are fitted (as in case of centre longitudinal bulkhead), transverse bulkheads in wing tanks are to be examined.

7) For vessels converted from single to double hull oil tankers, close-up examination for void spaces converted from cargo tanks:

Transverse double hull web frames including adjacent structural members (where wing cargo tank divided with new inner shell).

One - in each void space.

Transverses web frame rings including adjacent structural members (where wing cargo tank converted to void space).

One - in each void space.

Transverse bulkheads including girder system and adjacent structural members.

All - in all void spaces.

Source.: IACS UR Z10.4 TABLE I and Z10.3 TABLE I

Rules for Ships, January 2015

Pt.7 Ch.1 Sec.4 Renewal surveys extent main class Page 85

DET NORSKE VERITAS AS

Table 22 Minimum thickness measurements1), double hull oil tankers and double hull chemical tankers

Area Renewal survey no. 1

Age 5 years

Renewal survey no. 2

Age 5 - 10 years

Renewal survey no. 3

Age 10 - 15 years

Renewal survey no. 4 and subsequentAge > 15 years

0a Transverse section(s) within the cargo area 2)

One section of deck plating only - for the full beam of the ship 3)

One complete section 3)

Two complete sections - at least one within 0.5 L amidships 3)

Three complete sections - at least one within 0.5 L amidships 3)

0b Structural members subject to close-up examination according to Table 21.

Measurements, for general assessment and recording of corrosion pattern.

Measurements, for general assessment and recording of corrosion pattern.

Measurements, for general assessment andrecording of corrosion pattern.

Measurements, for generalassessment and recording of corrosion pattern.

1 Main deck plating All within the cargo area.

All - within the cargo area.

All - within the cargo area.All exposed - outside the cargo area.

2 Wind- and water strakes.

Selected outside the cargo area.

All - within the cargo area.Selected outside the cargo area.

All - full length.

3 Transverse bulkheads See item 0b See item 0b See item 0b See item 0b

4a Keel plates and bottom plates.

All keel plates full length. All bottom plates, including lower turn of bilge, within the cargo area.Additional bottom plates in way of cofferdams, machinery space and aft end of tanks.

4b Sea chests and shell plating in way of overboard discharges.

Plating of sea chests.Shell plating as considered necessary by the attending surveyor.

5 Superstructure deck plating (poop, bridge and forecastle deck).

Representative exposed deck plating.

6 Internals in peak tanks. Forepeak and aftpeak.

Forepeak and aftpeak.

Notes:

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

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

3) At least one section shall include a ballast tank, within 0.5L amidships, as far as applicable.

Source.: IACS UR Z10.4 TABLE II and Z10.3 TABLE II

DNV Requirement ts701 21DNV Requirement ts701 22