RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERS

Common Structural Rules for
Bulk Carriers, January 2006

Rule Change Notice 2
February 2008
Notes: (1) This Rule change shall apply to ships contracted for construction on orafter 1 July 2008. The Rule change may be adopted before 1 July 2008 at
the discretion of the Society.

Copyright in these Common Structural Rules for Bulk Carriers is owned by:American Bureau of Shipping
Bureau Veritas
China Classification Society
Det Norske Veritas
Germanischer Lloyd
Korean Register of Shipping
Lloyd's Register
Nippon Kaiji Kyokai
Registro Italiano Navale
Russian Maritime Register of Shipping
Copyright © 2006

The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are,individually and collectively, referred to in this clause as the ‘IACS Members’. The IACS Members, individuallyand collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expensecaused by reliance on the information or advice in this document or howsoever provided, unless that person has
signed a contract with the relevant IACS Member entity for the provision of this information or advice and in thatcase any responsibility or liability is exclusively on the terms and conditions set out in that contract.

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSFor technical background for Rule Changes in this present document, reference is made toseparate document Technical Background for Rule Change Notice 2.

CHAPTER 3 – STRUCTURAL DESIGN PRINCIPLESSECTION 6 STRUCTURAL ARRANGEMENT PRINCIPLES

9.

Deck structure

9.5

Hatch supporting structure

9.5.2
Clear of openings, adequate continuity of strength of longitudinal hatch coamings is
to be ensured by under deck girders.
The connection of hatch end beams to longitudinal girders and web frames is to beensured. Hatch end beams are to be aligned with transverse web frames in top sidetanks.
9.5.3
Clear of openings, adequate continuity of strength of longitudinal hatch coamings is
to be ensured by under deck girders.
At hatchway corners, the face plate of hatch coamings and longitudinal deck girders
or their extension parts provided under deck in line with hatch coamings and the faceplates of hatch end beams girders on both sides are to be effectively connected so as tomaintain the continuity in strength.

9.6

Openings in the strength deck

9.6.3

Corner of hatchways
For hatchways located within the cargo area, insert plates, whose thickness is to be
determined according to the formula given after, are generally to be fitted in way ofcorners where the plating cut-out has a circular profile.
The radius of circular corners is to be not less than 5% of the hatch width, where acontinuous longitudinal deck girder is fitted below the hatch coaming.
Corner radius, in the case of the arrangement of two or more hatchways athwartship,
is considered by the Society on a case by case basis.
For hatchways located within the cargo area, insert plates are, in general, not requiredin way of corners where the plating cut-out has an elliptical or parabolic profile andthe half axes of elliptical openings, or the half lengths of the parabolic arch, are notless than:• 1/20 of the hatchway width or 600 mm, whichever is the lesser, in the transverse
direction

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERS• twice the transverse dimension, in the fore and aft direction.
Where insert plates are required, their net thickness is to be obtained, in mm, from thefollowing formula:t INS = (0.8 + 0.4l / b ) t
without being taken less than t or greater than 1.6t
where:l :Width, in m, in way of the corner considered, of the cross deck strip between
two consecutive hatchways, measured in the longitudinal direction (see Fig 23)b :Width, in m, of the hatchway considered, measured in the transverse direction(see Fig 23)

t :Actual net thickness, in mm, of the deck at the side of the hatchways.

For the extreme corners of end hatchways, the thickness of insert plates is to be 60%
greater than the actual thickness of the adjacent deck plating. A lower thickness may
be accepted by the Society on the basis of calculations showing that stresses at hatch
corners are lower than permissible values.
Where insert plates are required, the arrangement is shown in Fig 25, in which d1, d2,
d3 and d4 are to be greater than the ordinary stiffener spacing.
For hatchways located outside the cargo area, a reduction in the thickness of theinsert plates in way of corners may be considered by the Society on a case by casebasis.
For ships having length L of 150 m or above, the corner radius, the thickness and theextent of insert plate may be determined by the results of a direct strength assessment
according to Ch 7, Sec 2 and Sec 3, including buckling check and fatigue strength
assessment of hatch corners according to Ch 8, Sec 5.

Figure 25:

Hatch corner insert plate

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSCHAPTER 4 – DESIGN LOADSSECTION 3 HULL GIRDER LOADS

2.

Still water loads

2.1

General2.1.2

Partially filled ballast tanks in ballast loading conditions
Ballast loading conditions involving partially filled peak and/or other ballast tanks at
departure, arrival or during intermediate conditions are not permitted to be used as
design conditions unless:•design stress limits are satisfied for all filling levels between empty and full, and•for BC-A and BC-B ships, longitudinal strength of hull girder in flooded
condition according to Ch 5, Sec 1, [2.1.3] is complied with for all filling levels
between empty and full.

However, for the purpose of design, it is acceptable if, in each condition at departure,arrival and, where required by [2.1.1], any intermediate condition, the tanks intended
to be partially filled are assumed to be empty and full.
In addition, the specified partly filled level in the intended condition is to beconsidered.
To demonstrate compliance with all filling levels between empty and full, it will be
acceptable if, in each condition at departure, arrival, and where required by [2.1.1],
any intermediate condition, the tanks intended to be partially filled are assumed to
be:
•

empty

•

full

•

partially filled at intended level

Where multiple tanks are intended to be partially filled, all combinations of empty,
full or partially filled at intended level for those tanks are to be investigated.

2.1.4

Sequential ballast water exchange
Requirements of [2.1.2] and [2.1.3] are not applicable to ballast water exchange using
the sequential method.

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSCHAPTER 9 – OTHER STRUCTURESSECTION 2 AFT PART

5.

Connection of hull structures with the rudder horn

5.1

Connection of aft peak structures with the rudder horn

5.1.3

Hull structures
Between the horn intersection with the shell and the peak tank top, the verticalextension of the hull structures is to be not less than the horn height, defined as the
distance from the horn intersection with the shell to the mid-point of the lower horn
gudgeon.
The vertical extension of hull structure to support the rudder horn between the hornintersection with the shell and the peak tank top is in accordance with therequirements of Ch 10, Sec 1, [9.2.6] and [9.2.7].
The thickness of the structures adjacent to the rudder horn, such as shell plating,floors, platforms and side girders, the centreline bulkhead and any other structures, isto be adequately increased in relation to the horn scantlings.

SECTION 4 SUPERSTRUCTURES AND DECKHOUSES

5.

Superstructure end bulkheads and deckhouse walls End bulkheads ofsuperstructure and deckhouse

5.1

Application

5.1.1

The requirements in 5.2 and 5.3 apply to end bulkhead of superstructure anddeckhouse superstructure end bulkheads and deckhouse walls forming the only
protection for openings, are required by ILLC as amended, and for accommodation.

5.3

Scantling

5.3.1

Stiffeners
The section modulus w, in cm3, and the shear area Ash, in cm2, of the stiffeners is not tobe less than the value obtained from the following formula:w = 0.35kp A sl 2This requirement assume the webs of lowest tier stiffeners to be efficiently welded tothe decks. Scantlings for other types of end connections may be specially considered.

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSThe section modulus of deckhouse side stiffeners needs not to be greater than that ofside frames on the deck situated directly below; taking account of spacing s and spanl.

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RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSCHAPTER 13 – SHIPS IN OPERATION, RENEWALCRITERIA
SECTION 1 MAINTENANCE OF CLASS

1.

General

1.2

Definitions

1.2.2

Substantial corrosion
Substantial corrosion is an extent of corrosion such that assessment of the corrosion
pattern indicates a wastage in excess of 75% of allowable margins but within
acceptable limits gauged (or measured) thickness between trenewal and trenewal + treserve.
The allowable margin is the total corrosion addition tC, as defined in Ch 3, Sec 3.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERS

Common Structural Rules for
Bulk Carriers, January 2006

Technical Background forRule Change Notice 2
February 2008

Copyright in these Common Structural Rules for Bulk Carriers is owned by:American Bureau of Shipping
Bureau Veritas
China Classification Society
Det Norske Veritas
Germanischer Lloyd
Korean Register of Shipping
Lloyd's Register
Nippon Kaiji Kyokai
Registro Italiano Navale
Russian Maritime Register of Shipping
Copyright © 2006

The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are,individually and collectively, referred to in this clause as the ‘IACS Members’. The IACS Members, individuallyand collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expensecaused by reliance on the information or advice in this document or howsoever provided, unless that person has
signed a contract with the relevant IACS Member entity for the provision of this information or advice and in thatcase any responsibility or liability is exclusively on the terms and conditions set out in that contract.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERSTechnical Background for the Changes in:
Chapter 3/Section 6/9.5.2
1.

Reason for the Rule Change:

Chapter 3/Section 6/9.5.2
This change is made to clarify the requirement.
In order to clarify the requirement, the first sentence is moved to 9.5.3.
2.

Impact on Scantling

There is no change in terms of the steel weight by comparing that before and after the
proposed Rule change.

Chapter 3/Section 6/9.5.3
1.

Reason for the Rule Change:

Chapter 3/Section 6/9.5.3
The change is made to clarify the requirement.
The word “the face plate of” was deleted, taking into account the current design of BC.
2.

Impact on Scantling

There is no change in terms of the steel weight by comparing that before and after the
proposed Rule change.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2

Chapter 3/Section 6/9.6.3
1.

COMMON STRUCTURAL RULES FOR BULK CARRIERSCorner of hatchways

Reason for the Rule Change:

Chapter 3/Section 6/9.6.3
For ships having length L of 150 m and above, FEA including buckling check, hull girder
ultimate strength check and fatigue check of hatch corners are required by the CSR for bulk
carriers.
Therefore, it is considered that the extent of insert plate can be determined based on such
evaluation result in lieu of the requirement of this sub-section.

2.

Impact on Scantling

There may be slight change in terms of the steel weight by comparing that before and after
the proposed Rule change. In any case, however, there is no influence for on the structural
integrity of the ship.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERS

Chapter 4/Section 3/2.1.2 and 2.1.4
1.

Reason for the Rule Change:

Chapter 4/Section 3/2.1.2 and 2.1.4
This rule change is made to be in line with the revision 5 (Jan 2005) of IACS UR S11.
The last 2 sentences of [2.1.2] and new paragraph [2.1.4] correspond to the applicable parts of
IACS UR S11.2.1.3 and S11.2.1.5 respectively.

2.

Impact on Scantling

The rule change proposal has no impact on scantling as the IACS UR S11 should have been
applied by designer. No consequence assessment is considered necessary.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2

Chapter 9/Section 2/5.1.3
1.

COMMON STRUCTURAL RULES FOR BULK CARRIERS

Hull structures

Reason for the Rule Change:

Chapter 9/Section 2/5.1.3
A significant number of questions and comments have been raised with respect to thevertical extension of the internals in way of the rudder horn (e.g., aft peak floors). When thevertical extension is required not to be less than the horn height, defined as the distance fromthe horn intersection with the shell to the mid-point of the lower horn gudgeon, it is quite
different from the current designs and designers have indicated that this is excessive.
The change is made so that the required vertical extension becomes practical and a crossreference to the floor and girder requirements of Ch.10, Sec.1 [9.2.6] and 9.2.7] is provided.
The requirements of Ch.10, Sec.1 [9.2.6] through [9.2.10] include general prescriptive
requirements for the strengthening and alignment of floors and girders in way of the rudder
horn. These prescriptive requirements have been shown to provide adequate stiffness in thestern construction area in order to support the rudder forces and to prevent unfavourable
hull vibration due to the propeller wake, as they are similar to the existing rules which haveresulted in sufficient structure. The aft peak structure in the vicinity of the attachment ofhorn, peak tank plate and closely spaced floors, can fairly distribute rudder force into hull
structures. As is the case with any other part of the structure, unless there is some unusual
or novel arrangement, further detailed analytical checks are not considered necessary.
The connection of the rudder horn is handled in CSR for Double Hull Oil Tankers 8/5.2.2.3
and are fairly similar to the above mentioned Ch.10 Sec. 1 [9.2.6] through [9.2.10].

2.

Impact on Scantling

There may be slight change in terms of the steel weight by comparing that before and after
the proposed Rule change. In any case, however, there is no influence on the structural
integrity of the ship.

Chapter 9/Section 4/5 & 5.1.1

Application

Considering the comments from Technical Committee, the editorial correction of the title of
Ch 9 Sec 4 [5] and the text of Ch 9 Sec 4 [5.1.1] is made to be in line with IACS UR S 3.

Chapter 9/Section 4/5.3.1

Stiffeners

There is no formula for required shear area for stiffeners of end bulkheads of superstructureand deckhouses. Therefore, the corresponding words are deleted.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2COMMON STRUCTURAL RULES FOR BULK CARRIERS

There is no formula for required shear area for stiffeners of superstructure end bulkheads
and deckhouses wall.
Therefore, the corresponding words are deleted.
2.

Impact on Scantling

There is no change in terms of the steel weight by comparing that before and after the
proposed Rule change.

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TECHNICAL BACKGROUND FOR RULE CHANGE NOTICE 2

Chapter 13/Section 1/1.2.2
1.

COMMON STRUCTURAL RULES FOR BULK CARRIERS

Substantial corrosion

Reason for the Rule Change:

Chapter 13/Section 1/1.2.2
This change is made to be consistent with Chapter 13/Section 2/3.2.2 and IACS UR
Z10.2.1.2.11 (Rev. 22 June 2006).

2.

Impact on Scantling

There is no change in terms of the steel weight by comparing that before and after the
proposed Rule change.

*****

End

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