SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.1/PAGE 1
1 G
ENERAL1.1 Introduction
1.1.1 Scope
1.1.1.1 This section covers the general structural arrangement requirements for the ship, which are based on or derived from National and International regulations, see Sections 2/2.1.1 and 3/3.3.
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.2/PAGE 1
2 W
ATERTIGHTS
UBDIVISION2.1 Watertight Bulkhead Arrangement 2.1.1 General
2.1.1.1 All ships are to be provided with watertight bulkheads arranged to subdivide the hull into watertight compartments in accordance with the following requirements.
2.1.2 Minimum number and disposition of watertight bulkheads
2.1.2.1 The following watertight bulkheads are to be fitted on all ships:(a) a collision bulkhead, see 2.2.1.1 (b) an aft peak bulkhead
(c) a bulkhead at each end of the machinery space.
2.1.2.2 The bulkheads in the cargo tank region are to be spaced at uniform intervals so far as practicable.
2.1.2.3 The applicable number and disposition of bulkheads are to be arranged to suit the requirements for subdivision, floodability and damage stability, and are to be in accordance with the requirements of National regulations.
2.1.2.4 The number of openings in watertight bulkheads is to be kept to a minimum. Where penetrations of watertight bulkheads and internal decks are necessary for access, piping, ventilation, electrical cables, etc., arrangements are to be made to maintain the watertight integrity. Additional requirements apply to collision bulkheads in Section 8/3.6.2.
2.2 Position of Collision Bulkhead 2.2.1 General
2.2.1.1 A collision bulkhead is to be fitted on all ships and is to extend to the freeboard deck. It is to be located between 0.05LL or 10m, whicheveris less, and 0.08LL aft of the reference point, where the load line length, LL, is as defined in Section 4/1.1.2.1 and the reference point is as defined in 2.2.1.2. Proposals for location of the collision bulkhead aft of 0.08LL will be specially considered.
2.2.1.2 For ships without bulbous bows the reference point is to be taken where the forward end of LL coincides with the forward side of the stem, on the waterline which LL is measured. For ships with bulbous bows, it is to be measured from the forward end of LL a distance x forward; where x is to be taken as the lesser of the following:
(a) half the distance, from the forward end of LL and the extreme forward end of the bulb extension
(b) 0.015LL
(c) 3.0m.
2.2.1.3 In general, the collision bulkhead is to be in one plane, however, the bulkhead may have steps or recesses provided they are in compliance with the limits prescribed in 2.2.1.1 and 2.2.1.2.
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.2/PAGE 2
2.3 Position of Aft Peak Bulkhead 2.3.1 General
2.3.1.1 An aft peak bulkhead, enclosing the stern tube and rudder trunk in a watertight compartment, is to be provided. Where the shafting arrangements make enclosure of the stern tube in a watertight compartment impractical, alternative arrangements will be specially considered. The aft peak bulkhead location on ships powered and/or controlled by equipment that do not require the fitting of a stern tube and/or rudder trunk will also be subject to special consideration.
2.3.1.2 The aft peak bulkhead may terminate at the first deck above the summer load waterline, provided that this deck is made watertight to the stern or to a watertight transom floor.
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.3/PAGE 1
3 D
OUBLEH
ULLA
RRANGEMENT3.1 General
3.1.1 Protection of cargo tanks
3.1.1.1 Every tanker is to be provided with double bottom tanks and spaces, and double side tanks and spaces, in accordance with 3.2 and 3.3. The double bottom and double side tanks and spaces, protect the cargo tanks or spaces, and are not to be used for the carriage of oil cargoes.
3.1.2 Capacity of ballast tanks
3.1.2.1 The capacity of the segregated ballast tanks shall be so determined that the ship may operate safely on ballast voyages without recourses to the use of cargo tanks for water ballast. The capacity of ballast shall be at least such that, in any ballast condition at any part of the voyage, including the conditions consisting of lightweight plus segregated ballast only, the ships draught and trim can meet the requirements in 3.1.2.2 to 3.1.2.4.
3.1.2.2 The moulded draught amidships, Tmid, excluding any hogging or sagging correction, is not to be less than:
L Tmid =2 +.0 0.02 m Where:
L rule length, as defined in Section 4/1.1.1.1, in m
3.1.2.3 The draughts at the F.P. and A.P. are to correspond to those determined by the draught amidships, as given in 3.1.2.2, and in association with a trim by the stern not greater than 0.015L (m).
3.1.2.4 The draught at the A.P. is not to be less than that required to obtain full immersion of the propeller(s).
3.1.3 Limitation of size and arrangement of cargo tanks
3.1.3.1 Cargo tanks are to be of a size and arrangement that hypothetical oil outflow from side and bottom damage, anywhere in the length of the ship, is limited.
3.2 Double Bottom
3.2.1 Double bottom depth
3.2.1.1 The minimum double bottom depth, ddb, is to be taken as the lesser of:
15
ddb = B m, but not less than 1.0m 0
.
=2
ddb m Where:
B moulded breadth, in m, as defined in Section 4/1.1.3.1
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.3/PAGE 2
3.3 Double Side
3.3.1 Double side width
3.3.1.1 The minimum double side width, wds, is to be taken as the lesser of:
000 5 20
.
0 DWT
wds = + m, but not less than 1.0m 0
.
=2
wds m Where:
DWT deadweight of the ship, in tonnes, as defined in Section 4/1.1.14.1
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.4/PAGE 1
4 S
EPARATION OFS
PACES4.1 Separation of Cargo Tanks
4.1.1 General
4.1.1.1 The cargo pump room, cargo tanks, slop tanks and cofferdams are to be positioned forward of machinery spaces. Main cargo control stations, control stations, accommodation and service spaces are to be positioned aft of cargo tanks, slop tanks, and spaces which isolate cargo or slop tanks from machinery spaces, but not necessarily aft of the oil fuel bunker tanks and ballast tanks.
4.2 Cofferdam Spaces 4.2.1 General
4.2.1.1 Cofferdam spaces are to be kept gas-tight. Where applicable, access requirements to permit internal inspections, are to be in accordance with 5.3.
SECTION 5-STRUCTURAL ARRANGEMENT COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012 SECTION 5.5/PAGE 1
5 A
CCESSA
RRANGEMENTS5.1 Access Into and Within Spaces in, and Forward of, the Cargo Tank Region 5.1.1 General
5.1.1.1 Access into and within spaces in, and forward of, the cargo tank region is to satisfy the International Convention for the Safety of Life at Sea, 1974, as amended, Chapter II-1, Part A-1, Regulation 3-6, as required by the Flag Administration, for details and arrangements of openings and attachments to the hull structure. This will be reviewed in conjunction with the structural requirements. In addition, the requirements of 5.1.1.2 to 5.1.1.5 are to be complied with.
5.1.1.2 Where a duct keel or pipe tunnel is fitted provision is to be made for at least two exits to the open deck arranged at a maximum distance from each other. The duct keel or pipe tunnel is not to pass into machinery spaces. The aft access may lead from the pump room to the duct keel. Where an aft access is provided from the pump room to the duct keel, the access opening from the pump room to the duct keel is to be provided with an oil-tight cover plate or a watertight door. Mechanical ventilation is to be provided and such spaces are to be sufficiently ventilated prior to entry. A notice board is to be fitted at each entrance to the pipe tunnel stating that before any attempt is made to enter, the ventilating fan must have been in operation for a sufficient period. In addition, the atmosphere in the tunnel is to be sampled by a gas monitor, and where an inert gas system is fitted in cargo tanks, an oxygen monitor is to be provided.
5.1.1.3 Where a watertight door is fitted in the pump room for access to the duct keel, the scantlings of the watertight door are to comply with the requirements of the individual Classification Society and the following additional requirements:
(a) the watertight door is to be capable of being manually closed from outside the main pump room entrance, in addition to bridge operation. A means of indicating whether the door is open or closed is to be provided locally and on the bridge.
(b) a notice is to be affixed at each operating position to the effect that the watertight door is to be kept closed during normal operations of the ship, except when access to the pipe tunnel is required.
5.1.1.4 At least one horizontal access opening of 600mm by 800mm clear opening is to be fitted in each horizontal girder in the vertical wing ballast space and weather deck to assist in rescue operations. Where an opening of 600mm by 800mm is not permitted due to structural arrangements, a 600mm by 600mm clear opening will be accepted.
5.1.1.5 Special consideration will be given to any proposals to fit permanent repair/maintenance access openings with oil-tight covers in cargo tank bulkheads.
Attention is drawn to the relevant National regulations concerning load line and oil outflow aspects of such arrangements.
SECTION 6-MATERIALS AND WELDING COMMON STRUCTURAL RULES FOR OIL TANKERS
JULY 2012