IACS Common Structural Rules Knowledge Centre

Bulker Q&As and CIs on the IACS CSR Knowledge Centre
KCID
No.

Ref.

Type

Topic

Date
completed119

4/3.2.2.2

Questionwave
bending
moments

2006/8/18

What is the probability level of the vertical wave bending moments (Mwv.h)and (Mwv.s) used in the formulae defining the design still water bending
moments ?

The vertical wave bending moments (Mwv.h) and (Mwv.s) used in theformulae defining the design still water bending moments are at the probability
level of 10-8, i.e. calculated as defined in [3.1] with (fp) equal to 1.0.

176

4/App2/Ta
Questionb3

DSA
calculation

2006/9/27

The DSA calculation results in Loading condition No.10 in Table 3 of chapter
4, Appendix 2 are much larger than one in normal, especially for ships whose
length is less than 200m.

The loading condition No.10 in the Tab.3 of Chap.4, App.2 is extracted fromIACS UR S25, which is applicable to “Bulk Carriers” having length of 150m or
above. For ships having notation “BC-A” and length of 200m or less, scantling
impact are very large, comparing to those not applied to IACS UR S25.

When checking the condition under the ballast water exchange operation bymeans of the flow through method, static pressure for direct strength analysis
is specified in Ch 4, Sec 6, 2.1.2, but there is no description of dynamic
pressure.
1. Should the loading cases and wave conditions under consideration comply
2006/12/14
with the requirements of Ch 4, App 2?
2. The inertial pressure due to ballast is not to be considered according to therequirement in Ch 4, Sec 6, 2.2.1. Does this mean that only static pressure
due to ballast defined in Ch 4, Sec 6, 2.1.2 and external pressure defined in
Ch 4, Sec 5 are to be considered for direct strength analysis?

1. There is no need to comply with the requirements of Ch4App2. In theloading case specified in the loading manual with regard to ballast exchange,
the static load is considered for direct strength analysis.
2. Yes, the dynamic external pressure should be considered for direct strength
analysis.Where the ballast water exchange is carried out on the flow throughmethod, the direct strength analysis will be separately required on the ballast
water exchange condition in additional sea going ballast loading condition,
taking into account all EDWs.

226

280

4/6.2.1.2

Question

4/3.2.4.2 &Question
4/6.3.3.5

BWE

permeability

2007/1/8

Question/CI

Attachment

Answer

Minimum permeability of dry bulk cargoes:
According to CSR Ch.4 Sec.3 [2.4.2], it is stated that "appropriate permeability
We will consider the following interpretation on "appropriate permeability" andshould be used" while minimum permeability of 0.3 is also specified for ironthe treatment in flooded condition.
ore and cement. In addition, coal cargoes are mentioned in Ch.4 Sec.6- Minimum permeabilty value for grain to be 0,3.
[3.3.5]. For sake of order, minimum permeability should also be specified for- Determination of still water bending moment in flooded condition is to be
grain and other mineral ore materials. Unless other data is justified, we
based on actual loading conditions specified in the trim/stability booklet.
propose to define a minimum permeability of 0.5 for grain and 0.3 for other- Check of local strength check in flooded condition is to be based on cargomineral ore materials in addition to coal, cement and iron ore. The
density as defined in Table 1 of Ch.4/Sec.6.
permeability in Ch.4 Sec.6 [3.3.5] should be replaced by reference to Ch.4
Sec.3 [2.4.2].

Page 1 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

4/3.2.2.1 &4/3.2.2.2
283 & 5/1.4.2.1
Question
attc & 5/1.4.2.2& 5/1.4.2.4& 5/1.4.3.1

317

358

Ch 4/ 64/5.4.2.1

Topic

design stillwater
bending
moment

Question sea pressure

Questionbottomslamming

Datecompleted

Question/CI

Attachment

Answer

Question 1 . We assume the figure in attached file is related to the Fig 2 of Ch
4 Sec 3 [2.2.2] using the formulas of MSW,H & MSW,S and the extent within
0.4L amidships is shown by parallel line drawn in blue color in attached file. In
addition the values of the blue line at AE & FE should not be 0 but should becorrected as 0.2MSW in line with Fig 2 of Ch 4 Sec 3 [2.2.2]. At the end of thedesign process the still water bending moment used for scantling check and
FEA has to represent the individual envelope curve (CH4, Sec3, 2.1.1, first
sentence). This corresponds to the green line in the figures.
Question2 . Ch 4, Sec 3, [2.2.2] should be considered only as a preliminary
distribution of SWBM. It is not a minimum value of SWBM. Regarding thestrength point of view, the section modulus is to be checked according to its
minimum value (see Ch 5, Sec 1, [4.2.1] and [4.2.4]), and to its value basedon the permissible distribution of SWBM (see Ch 5, Sec 1, [4.2.2] and [4.3.1])
which may be the preliminary value of SWBM, if the permissible one comingfrom loading booklet is unknown.
Question 3. There is definition of a value of the SWBM in flooded condition. It
has to be calculated and included in the loading booklet and used for the
checking of hull girder strength according to Ch 5, Sec 1, [4.2.2] and [4.3.1], in
addition of the checks in intact condition.

2007/1/16

Design still water bending moments in CSR Bulk rules - 3 sub-questions withdiagrams (see attachment)

2007/1/12

According to Ch4, Sec5, [1.1.1] external sea pressure is defined assummation of hydrostatic pressure and hydrodynamic pressure but should not Regarding the first item, the answer is, "Yes". Your interpretation is correct.
be negative. However, Sec6 does not clearly specify whether negative
The total pressure obtained by adding the static pressure to dynamic pressurepressures are allowed in case of dry cargo or liquid. We would like to confirm is not to be negative as specified in Ch 5 Sec 1 [1.1.1].
if the following interpretation is acceptable.
This is the basic principle.
- Internal pressure due to dry cargo or liquid is to be obtained as summation of Regarding the second item, we assume that two kinds of internal pressurepressure in still water and inertial pressure but is not to be negative.
mean the example as shown in the question.
- In case where two kinds of internal pressures act on a considered location
The total internal pressure acting on one side of the boundary is not to beeach internal pressure is not to be negative.
negative and the total internal pressure acting on the opposite side of the
Example:boundary is also not to be negative, according to the basic principle as
In case of bulkhead plate between No.4 and 5 holds
mentioned above.
From No.4: Static=100, Inertial=-80, Sum=20
The grand total pressure acting on the boundary is obtained from the
From No.5: Static=60, Inertial=-80, Sum=0
difference between both internal pressure.
(Differential pressure=20)

2007/2/22

Ch4 Sec5 [4.2.1] specifies the design bottom slamming pressure. The
pressure is defined from almost 0.5L to fore end. Ch9 Sec1 [5] specifies therequired sturctural scantlings using the pressure. However the strengthening
required by Ch9 is forward of 0.2Vx(root L) from fore perpendicular end.There
Your undestanding is correct.
may be a zone between abt. 0.5L and 0.2Vx(root L) where there is norequirement to structural scantlings in Ch6 using the slamming pressure.
Please confirm that there is no scantling requirement in this zone using theslamming prressure.

Page 2 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

364

401

Ref.

4/6.3.2.1

4/7.3.4,
4/2.2.1.1,
4/App.2.
Table 1

Type

Topic

Question

VerticalAcceleration

Discription of
Symbols of
Question"Kr" and"GM"

Datecompleted2007/3/20

2007/7/1

Question/CI

In flooding scenario, do we apply the vertical acceleration aZ for “intact”
condition as defined in Ch 4 Sec 2 [3.2.1]?

According to CH 4, Sec 7, 3.4 Cargo holds have to be loaded with atheoretical cargo mass [t] of M_HD + 0.1 x M_H with rho = 3 t/m. This loading
condition has to be used for prescriptive requirements as defined in CH 6 andFEA. Such a concentrated load has a significant higher GM than inhomogeneous full load condition. Table 1 of Ch 4, Sec 2 takes the different
loading conditions (alternate / homogeneous) not into account.
(1)Is it correct, to consider the described loading condition for prescriptive
requirements?
(2)If yes, the main influence for the dynamic loads are neglected by using thesame GM and k_r values for homogeneous full loading condition andalternate loading condition. Do we have to use the GM value for the alternate
full loading condition of the loading manual? (cargo masses are different!!!)(3)k_r values are not included in the loading manuals. Which formula can beused to derive k_r to the individual corresponding GM of the loading manual?
(4)In case of FEA, concentrated loading conditions have to be evaluatedaccording Ch 4, App. 2, Table 1 ff. In these cases the used GM values,
derived with Table 1 of Ch 4, Sec 2 are wrong. It should be recommended,that only GM values defined in the loading manual have to be used for theseanalyses.

Attachment

AnswerYes. The draft and total weight of ships in intact condition is slightly different
from those in flooded condition. But the difference is very small and there is no
significant effect due to flooding for the acceleration or the motion of a ship.
Therefore, the vertical acceleration az for “intact condition” is applied to theformula in flooded condition specified in Ch 4 Sec 2 [3.2.1].

As specified in the description of symbols of “Kr” and “GM” in 2.1.1 of Ch 4
Sec 2, when the value of Kr and GM are not known, the values indicated inTable 1 may be assumed. This means that the actual values of Kr and GM in
the loading manual should be used in the calculations of the ships motions
and accelerations in Ch 4 Sec 2 as a principle.
The values of GM and Kr indicated in Table 1 have been proposed as the
typical and actual values for usual conditions such as the full alternate or
homogeneous load condition (even distribution of mass in transverse section)in order to provide these values when they are not known at the initial stage.

Page 3 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

406

Ref.

4/6.3.3.2,
Symbol4.6, 4/6.1

Type

Topic

Date
completed

Question/CI

Attachment

Answer

Questions related to interpretation of the pressure in Ch. 4 Sec.6 :Q1 Ch.4 Sec.6 [3.3.2]
Please advise how to check the load scenario as stated in the last sentence of
Ch.4 Sec.6 [3.3.2] which reads; "the maximum mass of cargo which may be
carried in the hold is also to be considered to fill that hold up to the upper deck
level at centreline."
Cargo density is given in Ch.4 Sec.6 [Symbols] when the hold is filled up to
the upper deck for BC-A and BC-B. This however assumes homogeneous
loaded condition Mh at maximum draught.

CI

Pressure

A1 For bulkhead strength check under flooded condition, the cargo mass,cargo density and cargo upper surface are as follows.
(1)Homogeneous loading condition(a)Cargo density is less than 1.78 t/m3
Cargo Mass: The maximum cargo mass in case where the cargo is loaded up
to the upper deck in homogeneous loading condition at maximum draught.
Cargo density: According to loading manual
Upper surface of cargo: Upper deck level at center line of cargo hold.
2007/10/23
Q2 Ch.4 Sec.6 [Symbols]
However, for hold of cylindrical shape, the upper surface of cargo may be
Do we not check alternate full hold in BC-A vessel filled up to upper deck?
evaluated by the requirement of 1.1.1.
•As far as we understand, this is not in line with URS18 and Ch4 Sec.6 [3.3.2] (b)Cargo density is not less than 1.78 t/m3
•Regarding intact condition for BCA. Only rho = 3 is to be checked according Cargo Mass: The maximum cargo mass in case where the cargo is not loaded
to Ch.4Sec.6 [Symbols] E.g. for ships are set up with cement loading in
up to the upper deck in alternate loading condition at maximum draught.
alternate condition, at least two conditions should be calculated as they are
Cargo density: According to the loading manual
decisive for different elements. Cond 1: M = MHD +10%MH with density, rho= Upper surface of cargo: The upper surface of cargo can be obtained by the3 ReposeAngle=35 deg. Cond 2: M = MHD +10%MH with density, rho= 1.25 formula specified in 1.1.2.
ReposeAngle=25 deg.
Please consider revising.
Q3: Ch. 4 Sec.6 [1]Equivalent cargo filling height hc is calculated according to Ch.4 Sec.6 [1.1.1]
when the cargo hold is loaded "up to the top of hatch coaming". This does notcorrespond to the load scenario in [3.3.2] as mentioned above "to fill that hold"up to the upper deck level at centerline". The same applies for the fillingheight as defined in the last sentence in [1.1.2]. Please clarify.

(2)Alternate loading condition(a)Cargo density is less than 1.78 t/m3
Cargo Mass: The maximum cargo mass in case where the cargo is loaded up
to the upper deck in alternate loading condition at maximum draught.
Cargo density: According to loading manual
Upper surface of cargo: Upper deck level at center line of cargo hold.
Q4: Ch. 4 Sec.6 [1]However, for hold of cylindrical shape, the upper surface of cargo may be
According to Ch.4 Sec.6 [3.3.3], the load scenario with cargo density 1.78
evaluated by the requirement of 1.1.1.
t/m3 at flooding level of 0.9D1 can be a dimensioning load case for bending(b)Cargo density is not less than 1.78 t/m3
capacity of vertical corrugation in flooded condition. In this load scenario,
Cargo Mass: The maximum cargo mass in case where the cargo is not loadedcargo hold is normally not loaded up to the upper deck.
up to the upper deck in alternate loading condition at maximum draught.
How to calculate hc according to Ch.4 Sec.6 [1.1.2] when the cargo hold
Cargo density: According to the loading manual(alternate full hold in BC-A vessel) is not filled up to upper deck. Cargo surface
Upper surface of cargo: The upper surface of cargo can be obtained by theis close to upper deck touching the topside tank sloping bottom. This is notformula specified in 1.1.2.
assumed in the formula as illustrated in Figure 4.6.2. Please clarify.

A2 The 2nd sentence in Ch.4 Sec.6 [3.3.2] reads:"The most severe
combinations of cargo induced loads and flooding loads are to be used for the
check of the scantlings of each bulkhead .....". Accordingly if the cement
loading in alternate loading should be the severest, transverse verticallycorrugated watertight bulkheads needs to be checked in such condition.
Therefore there is no need to change the current rules.
(Continues to the next page)

Page 4 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

406

Ref.

4/6.3.3.2,
Symbol4.6, 4/6.1

Type

CI

Topic

Pressure

Datecompleted2007/10/23 (Refer to the former page)

Question/CI

Attachment

Answer(Continuation of the former page)A3 The filling height specified in the requirement of 1.1.1 of Ch 4 Sec 6 isbased on the experiments and their findings to evaluate the cargo load underintact condition. Hence, it is different from the load scenario for flooded
condition which the permeability should be considered in addition to the cargo
filling height. But in order to estimate the cargo filling height for non-cylindricalshape by ample and easy procedure, the last sentence of 1.1.2 can be accept
the same procedure on cargo filling height under flooded condition.
A4 When the cargo is not loaded up to the upper deck but close to upper decktouching the topside tank sloping plate, the cargo filling height can be obtainedby the requirement of 1.1.2 neglecting the topside tank.

Page 5 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

456

Ref.

4/6.2.2.1

Type

CI

Topic

Ballast waterexchangeDatecompleted2007/7/13

Question/CI

Attachment

Answer

It is considered literal that Ch.4, Sec.6-2.2.1 ruling out the inertial pressure isframed on the assumption that a ballast water exchange by means of flowthrough method is carried out in calm sea and dynamic pressure (inertialpressure) is ignored. In that case, the following interpretations to be clarified
arise when calculating lateral pressures due to liquid.
(1) External pressure
When considering external (sea) and internal (ballast water) pressuressimultaneously according to Ch.6, Sec.1-1.3.1, it should be possible that theexternal dynamic pressure (hydrodynamic pressure) is similarly ignored bothfor prescriptive Rule calculations and Direct Strength Assessment (DSA).
(2) Wave bending moment
It should be possible that vertical and horizontal bending moments are ignored
Unless the external dynamic pressure and hull girder wave moment areboth for prescriptive Rule calculations (e.g. Ch.6, Sec.1-3.1.5) and DSA.
considered for local scantling check and DSA as you mentioned, all scantlings(3) Question ID:226
Should the above interpretations be the case, it is considered necessary that of hull structure are not determined in such load conditions. Then, we madethe answer specified in KC 226.
the Q&A ID:226 about DSA as quoted below is reviewed.
On the other hand, in tanker CSR, all dynamic loads are considered based on*****QUOTE*****
the assumption that a ballast water exchange by means of flow-throughQuestion ID: 226 Approved: 12/01/07
method is carried out in sea going condition.
Rule Ref.: Text 4/6.2.1.2
Question:
We think this assumption should be harmonized between tanker CSR and
When checking the condition under the ballast water exchange operation bymeans of the flow through method, static pressure for direct strength analysis bulker CSR.
is specified in Ch 4, Sec 6, 2.1.2, but there is no description of dynamic
Therefore, the interpretation is not necessary and the answer specified in KC
pressure.
1. Should the loading cases and wave conditions under consideration comply 226 is kept as it is, till harmonization work will be done.
with the requirements of Ch 4, App 2?
2. The inertial pressure due to ballast is not to be considered according to therequirement in Ch 4, Sec 6, 2.2.1. Does this mean that only static pressure
due to ballast defined in Ch 4, Sec 6, 2.1.2 and external pressure defined in
Ch 4, Sec 5 are to be considered for direct strength analysis?
Answer:1. There is no need to comply with the requirements of Ch4App2. In theloading case specified in the loading manual with regard to ballast exchange,
the static load is considered for direct strength analysis.
2. Yes, the dynamic external pressure should be considered for direct strength
analysis. Where the ballast water exchange is carried out on the flow throughmethod, the direct
strength analysis will be separately required on the ballast water exchange
condition in
additional sea going ballast loading condition, taking into account all EDWs.
*****UNQUOTE*****

Page 6 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

465
attc

Ref.

4/7.2.2.1

Type

Question

Topic

BallastConditions

Datecompleted2007/7/12

Question/CI

Attachment

Answer

According to Background document for CSR BC, Page 26 – Ch 4: Design
Loads, it is said the regulation on ballast tank capacity and disposition is inaccordance with IACS UR S25. IACS URS25: 4.4.1(b) Heavy ballast
condition:ii. at least one cargo hold adapted for carriage of water ballast at sea, whererequired or provided, is to be full.
CSR BC, Ch 4, Sec 7:Heavy ballast condition:
Heavy ballast condition is a ballast (no cargo) condition where: at least one
cargo hold adapted for carriage of water ballast at sea is to be full.
In CSR for Bulker, a heavy ballast condition is considered as a ballast
My understanding to UR S25 is that cargo hold for water ballast is just an
condition where at least one cargo hold adapted for carriage of water ballast
option or choice, not definitely/mandatorily required by UR S25. But if required at sea is full.
or provided as necessary, then it is to be full in heavy ballast condition.
If a ship does not have a cargo hold for carriage of water ballast, heavy ballast
While according to CSR BC, the condition clause "where required or provided" condition does not exist in such a ship in CSR for Bulker.
in UR S25 was deleted in CSR BC, then at least one cargo hold for waterballastIn addition, providing a cargo hold for carriage of water ballast to a ship is notshould be arranged. Do you think this requirement in UR S25 is consistentmandatory in CSR for Bulker.
with that in CSR BC? As to BC of Double Side Skin Structure, if ballast tankwith enough capacity, should at least one cargo hold also used as water
Regarding the multi-purpose container vessel, CSR for Bulker does not apply
ballast tank?
to such a kind of ship.
The attached is the typical section of a ship, normally considered as multipurpose container vessel. In my opinion/understanding, CSR BC does not
apply to such a kind of ship, but shipowner want to have the notation of BC
and CSR. If as required by CSR BC, at least one cargo hold should be as
water ballast. There are double rows of hatches in weather deck, then how to
calculate the internal pressure on weather deck and hatch cover? Can we
calculate the internal pressure on weather deck and hatch cover seperately
for each hatch assuming the central longitudinal box girder as longitudinalbulkhead? It's very difficult to arrange the locking device to resist the upward
force due to internal pressure.

Could you confirm that for CSR-BC internal pressure:
1. The total pressure (pcs+pcw) should not be negative471

4/6.1.1.1 &Question
4/6.1.1.2

CSR-BC
internalpressure

2007/7/11

2. For loading condition where the cargo hold is loaded to the upper deck
(Chapter 4, section 6, 1.1.1), for the point above the local height HC,(i) The static pressure PCs is zero(ii) The vertical dynamic pressure az KC aZ (hC + hDB − z) is zero(iii) Therefore PCW =ρC *0.25aY (y − yG )3. For loading condition where the cargo hold is not loaded to the upper deck
(Chapter 4, section 6, 1.1.2) for the point above the local height HC,(i) The static pressure PCS is zero(ii) The dynamic pressure PCW is zero.

A1. Your understanding is correct: the total pressure (pcs+pcw) should not be
negative.
A2. For loading condition where the cargo hold is loaded to the upper deck
(Ch 4, Sec 6, 1.1.1), for the point above the local height HC: the staticpressure and the inertial pressure pCW are equal to zero.
A3. For loading condition where the cargo hold is not loaded to the upper deck
(Ch 4, Sec 6, 1.1.2) for the point above the local height HC, the static pressure
and the inertial pressure pCW are equal to zero.

Page 7 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

474

Ref.

Ch.4
App.1

Type

CI

Topic

Determining
the holdmass curves

Datecompleted2007/7/2

Question/CI

Attachment

AnswerA1) CSR regulates to determine the maximum allowable mass and theminimum required mass of the hold mass curve on basis of strength
estimation in Ch4 Sec7, App1 and App2. The maximum allowable mass refers
to the loading mass at the strength estimation in full load condition. Filling ratein the double bottom in full load condition tanks is regulated as follows;a. FOT: Full
b. WBT: Empty
a. Carriage in DBFOT in full loading condition in the strength estimation isassumed full as the most severe situation. The mass in DBFOT is notnecessary to be considered when generating and utilizing the hold mass
curve.
Ch. 4 Appendix 1:
b. Carriage in DBWBT in full loading condition in the strength estimation is1) When determining the hold mass curves according to Appendix 1 weassumed empty as the standard loading pattern. If water ballast is carried inassume that weight of masses concealed in the double bottom in between
DBT in full loading condition, the strength estimation including such loading
margin girders are to be considered both when generating the hold mass
curves and when utilizing them in operation phase. (E.g. Heavy fuel oil, water condition should be carried out also. Namely full loading condition with full
DBWBT, should be considered in the strength estimation as the most severe
ballast) Please confirm.
2) Please advise how to handle ship trim both when generating the hold mass condition. In such case, the mass in DBWBT is not necessary to be
curves and later when utilizing the curves. Please consider a rule clarification. considered when generating and utilizing the hold mass curve.
A2)Trim should be taken into account as follows as similar to UR S1A.2.1
requirements:(i)Maximum allowable and minimum required mass of cargo and double
bottom contents of each hold to be as a function of the draught at mid-holdpoistion(ii)Maximum allowable and minimum required mass of cargo and double
bottom contents of any two adjacent holds to be as a function of the mean
draught in way of these holds. This mean draught may be calculated byaveraging the draught of the two mid-hold positions.

478

479

4/5.3.4.1

4/5.3.4.1

CI

CI

Minimum
Lateralpressure

Definition of"n"

2007/8/3

2007/8/23

In Table 9, Minimum lateral pressure, P_Amin, is defined for the 4th tier with
P_Amin=2.5kN/m. In the GL-Rules this minimum pressure has a value of
12.5kN/m. Is this a typo?

This is a typo. The correct minimum pressure for the 4th tier and above is
12.5kN/m2.
Also Included in Corrigenda 5

Please explain in the definition of "n", what is the actual distance?

This is a typo. The complete sentence reads as follows:"However, where the actual distance (D-T) exceeds the minimum noncorrected tabular freeboard according to ILLC as amended by at least one
standard superstructure height as defined in Ch 1, Sec 4, [3.18.1], this tiermay be defined as the 2nd tier and the tier above as the 3rd tier." Thisdefinition based on the definition, given in IACS UR S3.
Also Included in Corrigenda 5

Page 8 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

485
attc

486

Ref.

Table
4.4.3

Ch 4 Sec
7

Type

CI

CI

Topic

Load
combination
factorLoading
conditions

Datecompleted

Question/CI

Attachment

Answer

2007/7/16“Load combination factors, LCF in Ch 4, Sec 4, Table 3, in the case that theencounter wave comes from the starboard side are left unspecified thus there
is a possibility of unnecessary confusion unless they are clarified, especially
When the starboard is the weather side, the reference hull girder loads andfor ships having unsymmetrical hull sections. Pease see the attachment and motions of ship and load combination factor are shown in the attached file.
confirm if the signs marked in red from what we understand are correct. If not,please supply correct signs together with technical backgrounds.”

2007/8/7

The loading conditions which are required by Ch.4 Sec 7 are only for checking 1 - The loading conditions which are required by Ch 4, Sec 7 are "artificial
loading conditions" considered for the check of strength.
the longitudinal strength, direct strength analysis and for capacity anddisposition of ballast tanks and stability purposes as mentioned in 1.2.4.
2 - Regarding flooding conditions, our interpretation is that they should have to
Therefore, these loading conditions will not included the loading manual but
be considered only for loading conditions defined in Ch 4, Sec 8, as they are
shall be just submitted for assessment of structure-wise.
really navigation conditions.
Above conditions will not be applied to hold flooding calculation andintermediate condition calculation.
Our understanding is that the loading condition required Ch.4 Sec 7 and Sec 8 3 - Regarding intermediate conditions required in Ch 4, Sec 3, [2.1.1], if
considered more severe, they are to be considered for loading conditions
have different concept.
defined in Ch 4, Sec 7 and Sec 8.
So when we check the hull structure strength, loading conditions required by
sec 7 should be necessary. And then the loading conditions should be" This answer is superseded by the anwswer to KC ID 622. Please referprepared in loading manual within permissible limit which is result of hullscantling
to KC ID 622"

Page 9 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

489

Ref.

4/6.1.3.1,
4/6.2.2.1,
4/5

Type

CI

Topic

Inertial
Pressures

Datecompleted2007/8/2

Question/CI

Attachment

AnswerInertial pressures Chapter. 4 Section 6
Reference is made to Ch. 4Section. 6 [1.3.1] “Inertial pressure due to bulk
cargo” and [2.2.1] “Inertial pressure due to liquid”. Both items have astatement that the longitudinal term may be “freezed” in x direction at two
points in the tank. According to [1.3.1] “ (x-xg) is to be taken at 0.25lH in theload case H1 or -0.25lH in the load case H2..(..)” Pressures from these twopoints may be utilized for local scantling according to Ch.6 and Ch.8.
Q1: Please advise if this statement is valid also for scantling of transversetank boundaries such as cargo hold bulkheads and plane bulkheads
separating BW tanks according to relevant requirements of Ch.6.
Q2: According to Ch. 6 Sec.1 [1.3.1] and Sec.2 [1.3.1] “(..) If the compartment
adjacent to the outer shell is intended to carry liquids, this still water and wave
A1: This requirement is also valid for scantling of tank boundaries.
internal pressures are to be reduced from the corresponding still water andA2: According to the Rule, “a” is correct.
wave external sea pressures.” When the internal pressure is constant in xdirection according to Ch. 4 Sec. 6 [2.2.1] what is the correct application of
Ch.6 Sec. 1 [1.3.1] and Sec.2 [1.3.1]?
Note. Ch. 4 Sec. 5 “External pressures” have no statement fixing the x
location.
a.Combine the internal pressure according to Ch. 4 Sec. 6 [2.2.1] with the sea
pressureat the x location consideredb.Combine the internal pressure according to Ch. 4 Sec.6 [2.2.1] with the sea
pressures
located at (x-xB) = 0.75 (H2) and -0.75 (H2) ?

490

Symbol
4.6

CI

DesignDensity forfuel oil2007/7/13

Ch. 4 Section 6 Symbols
The minimum design density for fuel oil is not specified in Ch.4 Sec.6
Please advise minimum rhoL for fuel oil to be used for strength verification
purpose.
Please consider updating the rules with this information.

CSR for bulk carrier does not specify the minimum design density for fuel oil.
The design density for fuel oil shall be determined by the designer or
shipbuilder with agreement of the owner.

Page 10 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

491

492

Ref.

4/7.2.1.1

4/7.2.1.4

Type

CI

Question

Topic

Deterninationof themaximumcargo massin cargoholds

Loading
conditions

Datecompleted

Question/CI

Answer

2007/7/2

Ch. 4 Sec. 7 [2.1.1]“For determination of the maximum cargo mass in cargo holds, the condition
corresponding to the ship being loaded at maximum draught with 50% ofconsumables is to be considered.”[2.1.1] is stating that a typical short voyage condition should be the basis forstrength verification. Please advise correct interpretation of this paragraph fora typical BC-A vessel.
“Empty holds”: Maximum cargo mass from loading manual is normally themass MH from homogenous condition. This mass is normally smaller than the
Mfull mass according to [3.2.1]. Maximum cargo mass in cargo hold istherefore Mfull. It is therefore assumed that [2.1.1] is automatically fulfilled for
empty holds. Please confirm.
“Ore loaded holds”: Maximum cargo mass MHD from the loading manual isnormally the maximum cargo mass in cargo holds. MHD + 10% MH is,according to [4.4.1], used for strength assessment.
Please advise if the mass MHD according to [2.1.4]/[3.2.1] should beestablished based on a short voyage condition with 50% consumables witheven filling at scantling draft.

According to the provision of [2.1.1] maximum cargo mass Mh or Mhd should
be obtained from loading conditions at full scantling draft and with 50%
consumables.
In general the maximum cargo mass (Mh) for an empty hold (Mh) corresponds
to the cargo mass in homogeneous full condition at scantling draft and with
50% consumables. Hence Mhd corresponds to the cargo mass in alternate
loading condition at scantling draft and with 50% consumables. Mfull is an
artificial cargo mass and the maximum permissible cargo mass for an empty
cargo hold in connection with the determination of hold mass curve.

2007/7/13

Ch. 4 Section 7 2.1.4 BC-A
Please consider following example.
1.BC-A vessel with minimum loading conditions as per Section Which comply
with both [2.1.1] and [2.1.4].
2.Additionally, vessel's loading manual has a short voyage alternate condition
with more severe filling than prescribed by minimum conditions as defined by
the item 1 above.
For strength verification of 2), should same rate of filling and cargo density as
per [2.1.4] be required for such short voyage condition?

Sea going condition and harbour condition are specified in CSR.
A short voyage condition is not specified in CSR but it is obvious that it is not a
harbour condition.
Therefore, where a short voyage alternate loading condition with more severe
filling than the minimum loading condition in [2.1.1] and [2.1.4] is specified in
the loading manual, strength check for such more severe loading condition
should be carried out in accordance with the CSR requirements.

Attachment

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IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

Topic

Date
completed

Question/CI

Attachment

Answer

Q1: In Ch.4 Sec.7 [1.2.4], it is stated that "the loading conditions listed in [2]are to be applied for the check of longitudinal strength ----, for capacity anddisposition of ballast tanks and stability purposes". Are these loading
conditions, which satisfy the departure and arrival conditions as stated in[2.3.1], intended to fulfil the requirements as stated in Sec.8 [2.2.2] and shallbe included in the vessel's Loading Manual?

501

4/7.1.2.4,
4/7.1.2.2, Question& 4/7.2.3.1

Loading
conditions

1 - The loading conditions which are required by Ch 4, Sec 7 are "artificial”
loading conditions" considered for the check of strength.
2 - Regarding flooding conditions, our interpretation is that they should have to
be considered only for loading conditions defined in Ch 4, Sec 8, as they arereally navigation conditions.
3 - Regarding intermediate conditions required in Ch 4, Sec 3, [2.1.1], if
considered more severe, they are to be considered for loading conditions
Q3: According to SOLAS Reg.V/22, navigation bridge visibility is required
defined in Ch 4, Sec 7 and Sec 8.
minimum "two ship lengths or 500 m, whichever is less". Is it required for the
A3: It is not necessary.
design loading conditions as stated in Ch.4 Sec.7 [2], which satisfy thedeparture and arrival conditions as stated in [2.3.1], to fulfil the bridge visibility A4: This requirement is the same of IACS UR S25 [4.5]requirements? We assume that any other loading conditions as stated in Ch.4
Sec.7 [1.2.2] shall satisfy the visibility requirements.
Q2: In Ch.4 Sec.7 [1.2.2], it is stated that "these requirements are notintended to prevent any other loading conditions to be included in the loading
manual ---." Does this mean that loading conditions required in Sec.8 [2.2.2]
can be different from those stated in Sec.7 [2]?

2007/8/2

Q4: In connection with the above, please also clarify what is meant by "Unlessotherwise specified" as stated in Ch.4 Sec.7 [2.3.1]. Who specifies what andwhere?
The correct formula is as follows.

515
attc

533

4/A1.3.1.2

4/5.4.1.1

RCP

RCP

The correct
formula todeal withdifferent
cargo massin each hold2007/10/22 Please see the attached file.

Flare angle"a"2007/9/19

Wmax(Ti) = MHD,fore + 0.1*MH,fore + MHD,aft + 0.1*MH,aft
Wmax(Ti) = MFull,fore + MFull,aftYwhichever is the greater, for Ts ≥ Ti ≥ 0.67*Ts in order to deal with possibly
different cargo mass in each hold.

With regard to the flare angle α, "α" is not defined in this paragraph.
So, please explain how to determine the "α" and add the definition of it.

The flare angle alpha at the load calculation point is to be measured in planeof the frame between a vertical line and the tangent to the side shell plating.
Also Included in Corrigenda 5

Page 12 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

549

565

Ref.

Table
4.6.2

4/6.3.3.6 &4/6.3.3.7

Type

Question

CI

Topic

Testing Loadheight of aballast holdNet
thinkness ofcorrugations

Datecompleted2007/10/9

2008/4/24

Question/CI

In table 2 of CH4, Sec6 the following formula is given for the testing loadheight of a ballast hold:z_st = z_h + 0,9
In the GL-Rules the same formula is the constant 2,5 instead of 0,9. What isthe basis of the additional height of 0,9m?
Mean height of a hatch cover, experimental results, sloshing effects?

Reference is made to KC#402 Q2. Quote:
Q2:Ref. Ch. 6 Sec. 1 [3.2.3] and Sec. 2 [3.2.6]
The item Ch. 6 Sec. 1 [3.2.2] is giving “Net thickness of corrugations (..) for
flooded conditions” and Sec. 2 [3.2.6] is giving “Bending capacity and shear
capacity (..) for flooded conditions.” Both items refer to the design resultant
pressure and resultant force as defined in Ch. 4 Sec. 6 [3.3.7].
Ch. 4 Sec. 6 [3.3.7] is defining the resultant pressure in combined bulk cargowater flooding. [3.3.6] is defining the pure water flooding pressures on
corrugations. This pressure seem to be overlooked in Ch.6. We assume thatthe reference to [3.3.6] is missing in Ch. 6.
Please consider revising the definition of p in Ch. 6 Sec. 1 [3.2.3] and Sec. 2[3.2.6] to "(..)either [3.3.6] or [3.3.7] whichever greater".
Q2 Answer: Ch 6, Sec 1, [3.2.2] and Sec 2, [3.2.6] are requirements comingfrom UR S18. The reference to the design resultant pressure in Ch 4, Sec 6,[3.3.7] only is fully in line with UR S18. Consequently, there is no need to add
any reference to [3.3.6].
Unquote.

Attachment

Answer

0.9m head is based on the item number 4 of Table 1 in IACS UR S14.

We agree that the pressures and forces on a corrugation on flooded empty
hold specified in Ch 4, Sec 6, [3.3.6] should be considered for scantling checkof corrugation in Ch 6, Sec 1, [3.2.3] and Ch 6, Sec 2, [3.2.6].
We will consider the rule change proposal in order to be in line with the 2nd
sentence of Ch 4, Sec 6, [3.3.2].

Please advise how Ch. 4 Sec. 6 [3.3.6] is accounted for when calculating theresultant pressure in [3.3.7]" or any other scantlings requirements. According
to Ch. 4 Sec. 6 [3.3.2], the 2nd sentence reads; "In any case, the pressure
due to the flooding water alone is to be considered" and the 4th line from thebottom reads; "For the purpose of this item, holds carrying packed cargoes
are to be considered as empty." We understand that the pf and Ff of [3.3.6]
deal with such cases but we can not find if they are referred to anywhere in
CSRB. Please advise.

Page 13 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

571
attc

604

Ref.

Ch4 App3
and Ch7
sec 4

Type

Question

1/4.2.1.1 &Question
4/3.2.4

Topicfatiguestrengthassessment

LongitudinalStrength
Calculation

Datecompleted

Question/CI

Answer

Attachment

A1. For fatigue strength assessment, the cargo density used is to be as much“realistic” as possible. Therefore, the cargo density according to Ch 4 App.3
should be used for fatigue strength assessment not only by direct analysis
specified in Ch 8 Sec 3 but also simplified method specified in Ch 8 Sec 4.
We will consider the rule change proposal accordingly
A2. We think that Ch 7 Sec 4 3.3.2 referred in the question is Ch 7 Sec 4 3.2.2
correctly. The the definition of lamda for "welded intersection between plane
plates" is applicable for intersection of two plates and intersection of plating
and bracket.
A3 The correction factor of Ch 7 Sec 4 [3.2.2] is applicable to the case where
the stress at the 0.5 t from the hot spot is slightly greater than the stress at the
1.5 t from the hot spot.

Y

2008/8/9

Please answer to the attached question for fatigue of Bulker CSR.

2008/5/6

It is mandatory to make Longitudinal Strength Calculation for one flooded holdfor Bulk Carriers having length of 150 m or above; according to SOLAS Ch.
XII Reg. 5. For that calculation the length of the ship is to be taken as Loadline
Length according to SOLAS Ch. XII Reg. 1
SOLAS Rule Reference: SOLAS Ch. XII Reg. 1 (for length definition) &SOLAS Ch. XII Reg. 5 (for Strength Calculation).
The rule length as defined in Ch 1, Sec 4, [3.1.1] should be used for the
According to CSR for Bulk Carriers the same calculation for flooded holddetermination of still water bending moment and still water shear force inshould be carried out but in CSR it is stated that the length of the ship is to be
flooded condition according to Ch 4, Sec 3, [2.4].
taken as the Rule Length.
CSR Rule Reference: CSR Ch.1 Sec. 4 2.1.1 (for length definition) & CSR
Ch.4 Sec. 3 2.4 (for Strength Calculation)
In our project, the Rule Length < 150 m while the Loadline Length > 150 m.
Would you please advise what kind of application should be followed? Should
the strength calculation be made in this particular case? Which length should
be taken into consideration?"

Page 14 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

622

Ref.

Ch.4,
Sec.7

Type

Question

Topic

Loading
conditions

Datecompleted2008/4/11

Question/CI

Attachment

AnswerAs you pointed out, CSR requirements for flooding conditions are the same as
those requirements of IACS UR S25 and S17.
The loading conditions defined in CSR Ch 4 Sec.7 [2], which come from IACS
UR S25.4, are to satisfy the requirement of the longitudinal strength in flooded
condition.
With regard to loading conditions used for flooding, KC ID. 486 says
The loading conditions for local strength defined in CSR Ch 4 Sec.7 [3], which‘Regarding flooding conditions, our interpretation is that they should have tocome from IACS UR S25.5 need not satisfy the requirement of the longitudinalbe considered only for loading conditions defined in Ch 4, Sec 8, as they arereally navigation conditions.’ This reply seems to mean that loading conditions strength in flooded condition.
define in Ch 4, Sec 7, which comes from UR S25, does not need to be applied Accordingly, the answer in KC ID #486 has now been modified as follows.
1. The loading conditions which are required by Ch 4, Sec 7 [3] are “artificial
to flooding.
loading condition” considered for the check of local strength only and need not
However, UR S25-2.2 and Note (2) clearly says that the loading conditions
satisfy longitudinal strength.
listed in UR S25-4 are to be used for the checking of rules criteria regarding
1bis. The loading conditions specified in Ch 4, Sec 7 [2] are required to checklongitudinal strength required by UR S17. It is our understanding that therequirements of the CSR BC Rules have to be the same as those of UR S25 the longitudinal strength and are to be described in the loading manual
specified in Ch 4 Sec 8.
since both are IACS requirements.
2.Regarding flooding condition, the loading conditions in Ch 4 Sec 7 [2] areHence it is requested to clarify the discrepancy above.
required to check the longitudinal strength.
3.Regarding intermediate conditions required in Ch 4, Sec 3, [2.1.1], if
considered more severe, they are to be considered for loading conditions
defined in Ch 4, Sec 7 and included in the loading manual specified in Ch 4,
Sec 8.

625

Ch.4,
Sec.5

CI

Ambiguity
found indetermining
x/L

2008/4/11

This question relates to the ambiguity found in determining x/L in the following
cases as x is on the global co-ordinate system whereas L is Rule length.
(i) In Ch.4, Sec.5, 1.3.1, clarification is requested in case x/L lies at a position
less than 0 or more than 1.0 in calculating kl.
(ii) In Ch.4, Sec.5, 1.3.1, clarification is requested in case |x-0.5L| lies at a
position less than 0 or more than 1.0 in calculating kp.
(iii) In Ch.4, Sec.5, 2.2.1, Table 4, clarification is requested in case x/LLL lies
at a position less than 0 or more than 1.0 in calculating pw.

A-1 If x/L is less than 0 or greater than 1.0, x/L is taken equal to 0 or 1.0,
respectively.
A-2 If x is less than 0 or greater than L, x is taken equal to 0 or x=L,
respectively.
A-3 If x/LLL is less than 0 or greater than 1.0, x/LLL is taken equal to 0 or 1.0
respectively.

Page 15 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

626

627
attc

Ref.

4/5.1.3.1

4/6.3.3

Type

Topic

CI

pHF When
the relevant
hull section
is totally
above thewaterline

CI

Floodedconditions forTransverse
verticallycorrugatedwatertightbulkheads

Datecompleted2008/2/21

Question/CI
This question relates to pHF(Ch4. Sec.5, 1.3.1) when the relevant hull section
is totally above the waterline.
It is noted that there are some totally above the waterline in the aft and fore
parts of ships in normal or heavy ballst condition. Bi at the location in theabove condition is regarded as 0.
When considering external pressure under H1, H2, F1 and F2, clarification on
how to calculate pHF is requested when Bi=0. Is |2y|/Bi=1 applicable?

Attachment

AnswerWhen the considered location is above the waterline, Bi is regarded as 0.
In this case, the pHF at the considered waterline is calculated assuming|2y|/Bi=1 and then the pressure at the considered location is correctedaccording to 1.6.1 of Ch 4 Se 5.

Regarding lateral pressures and forces in flooded conditions for Transverse
vertically corrugated watertight bulkheads (Ch.4, Sec.6-3.3) originated fromIACS UR S18, it should be that the density of dry bulk cargo (ρc) and cargo
filling level (hc) in Ch.4, Sec.6-3.3 are the same as for those in UR S18.
In calculating scantling of corrugated transverse bulkheads in flooded
conditions for BC-A ships, it is interpreted that the Rules are requiring
scantlings using the ρc defined in Table 1 of Ch.4, Sec.6 (probably, 1.0 for
homogeneous load condition and 3.0 for alternate load condition) and an
imaginary hc defined in Ch.4, Sec.6-1.1.
2008/2/21

If this is the case, the likelihood is that a required net scantling determined by We will consider the rule change proposal regarding flooding condition.
bending capacity is less than that required by UR S18 as in our experienced
cases where it is shown that a density such as 1.5 resulting from M_HD/V_H
with the cargo filling to deck at centre has frequently been critical. As shown in
our calculation attached, the required net bending capacity by the CSR BC
Rules is less than that by UR S18 by around 10 %.

Such being the case, it is considered neccessary to avoid a case where
scantlings less than those determined by applying UR S18 is accepted. To
this end, any density of dry bulk cargoes (ρc) and cargo filling to deck at
centre should be considered for flooded conditions.

Page 16 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

Topic

Date
completed

Question/CI

Attachment

AnswerWith respect to external pressures on exposed forecastle deck and a hatch
cover if arranged thereon, it is requested that the following are clarified.

Externalpressures on
4/5.2.2.1 &Question
exposed628
4/5.5.2.1
forecastle
deck

1. External pressures on freeboard deck and forecastle deck are explicit as
set out in Ch.4, S.5, 2.2.1. Tables 4 and 5, would lead you to believe that thepressure Pw on forecastle will be linearly increased to a maximum at the fore
perpendicular.
2008/5/28

2. It is our understanding that this is not the case as the linear increase inpressures is only applicable to exposed freeboard decks iaw Reg 16.2 of the1988 Protocol to the ILLC 1966 (Loadline Convention)

The assumption made by LR is right and we will consider the Rule change
proposal to clarify this issue.

3. If the coefficients in Tables 4 and 5 were applied the pressures on theforecastle would grow to such a disproportionate extent such as 90 kN/m2 ascompared to the constant pressure of 34.3 kN/m2 on a hatch cover applicableas set out in Ch.4, S.5, 5.2.1 and Regulation 16 (2) (d) in the 1988 Protocol to
the ILLC 1966 (LL Convention) defining Positions for hatchways.)

4.It is assumed that the conceptual background of the Rule is that pressureson exposed decks in Load Cases H1, H2, F1 and F2, are the same as thoseon hatchways in the LL Convention and the rules should be amended toreflect this more explicitly.
5. CSRPT1 should be requested to confirm our assumption and propose anamendment to the rules to clarify this issue.

633
attc

Ch.4,
Appendix
1

RCP

Hold Mass
Curves2008/7/2

A change of the Rules regarding hold mass curves set out in Ch.4, Appendix
1 is proposed as described in the attachment.
Hold mass curves are to be based on design loading conditions for local
strength as defined and specified in Ch. 4, Sec. 7, Para. 3 of the Rules.
However, it has been found that hold mass curves to be drawn up in apractical manner do not completely reflect the design loading conditions
defined in Ch.4, Sec.7, Para.3.

The content of the proposal will be studied and - if needed - the impact on
scantling will be quantified. This may lead to a Rule Change Proposal.

It is proposed that the Rules are part changed as drafted therein for review
and consideration, where the wordings underlined by red and the figuresrounded by red line denote the proposed changes.

Page 17 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

648

Ref.

4/5.4.2.1 &4/5.4.2.2

Type

CI

Topic

Designbottomslammingpressure

Datecompleted2008/7/2

Question/CI
Reference is made to Ch.4Sec.5 [4.2.1]/[4.2.2] Design bottom slammingpressure[4.2.1] TBFP “Smallest design ballast draught, in m, defined at forward
perpendicular for normal ballast conditions. Where the sequential method forballast water exchange is intended to be applied, TBFP is to be considered forthe sequence of exchange.”[4.2.2] “It is the master`s responsibility to observe, among other, the weather
conditions and the draught at forward perpendicular during water ballast
exchange operations, in particular when the forward draught during these
operations is less than TBFP. The above requirement and the draught TBFP
is to be clearly indicated in the operating manuals.”Technical background for CSR Bulk:
4.2.2.a To limit the slamming loads at acceptable level, the smallest design
ballast draught at forward perpendicular should only be undercut in cases
where bottom slamming is not expected.
Please comment our understanding

Attachment

AnswerAnswer 1-3: Yes with no need for further clarifications of rule text changes.
Answer 4:The minimum draught forward in case of heavy weather is indicatedon the shell-expansion and should be mentioned in the loading manual.
Draughts that undercut the "minimum draught forward in case of heavy
weather" are to be used at the masters descretion as per Ch4, Sec 5, [4.2.2].

(Continues to the next page)

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IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

Topic

Date
completed

Question/CI

Answer

Attachment(Continuation of the former page)648

4/5.4.2.1 &4/5.4.2.2

CI

Designbottomslammingpressure

2008/7/2

Q1. We assume the “smallest design ballast draught(..) for normal ballast
conditions” is referring to the ballast condition of Sec.7 [2.2.2]. Please confirm.
If yes, please add the reference in the rules for sake of clarity.
Q2. Regarding sequential ballast operation.
According to [4.2.1] “Where the sequential method for ballast water exchange(Refer to the former page)(..) is applied, TBFP is to be considered for the sequence of exchange”. Ch.4
Sec. 8 [2.2.2] require that “typical sequences for change at sea, whereapplicable” are included in the lading manual.
In order to evaluate [4.2.1] we understand that the loading sequence forballast exchange is required in the loaing manual in case of sequential ballast
operation.
Please confirm. If yes, please clarify rules.
Q3. Regarding sequential ballast operation.
We assume design draft for slamming, TBFP, is minimum among TBFP,
according to Sec7 [2.2.2] And TBFP, Ballast exchange in LM Sec8 [2.2.2]
Please advice. Please amend rules for clarity.
Q4. Masters responsibility.
According to [4.2.2] and CSR TB we understand that TBFP may be undercut if
weather permits.
If the loading manual includes more than one ballast exchange condition e.g:
WB Seagoing (Sec.7 [2.2.2]) TBFP = 7m
WB Exchange cond. 1 TBFP = 6 m
WB Exchange cond. 2 TBFP = 6.5 m
if no explicit request exist from designers, we assume TBFP for bottom
forward scantling may be chosen to be TBFP=6.5 m.
The limitation to TBFP will be stated in the vessel operating manual.
It is then the masters responsibility to utilize WB Exchange cond. 1 only when
weather permits according to [4.2.2]
Please advise.

Page 19 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

Topic

Date
completed

Question/CI

Attachment

Answer

Reference is made to Ch. 4 Sec. 7 [2.1.1] and KC Id. 491. In KC #491 we
asked the basis for MHD/MH according to [2.1.1] Quote Question: Ch. 4 Sec.
7 [2.1.1] “For determination of the maximum cargo mass in cargo holds, thecondition corresponding to the ship being loaded at maximum draught with
50% of consumables is to be considered.” [2.1.1] is stating that a typical shortvoyage condition should be the basis for strength verification. Please advise
correct interpretation of this paragraph for a typical BC-A vessel.

649

4/7.2.1.1

Question

Maximum
Cargo Mass

“Empty holds”: Maximum cargo mass from loading manual is normally themass MH from homogenous condition. This mass is normally smaller than the
Mfull mass according to [3.2.1]. Maximum cargo mass in cargo hold istherefore Mfull. It is therefore assumed that [2.1.1] is automatically fulfilled for
empty holds. Please confirm. “Ore loaded holds”: Maximum cargo mass MHD
from the loading manual is normally the maximum cargo mass in cargo holds. [2.1.1] is applicable only to [2.1.2] thru [2.1.4]. The latter paragraphs require
2008/10/10 MHD + 10% MH is, according to [4.4.1], used for strength assessment.
same filling ratio in all loaded cargo holds.
Please advise if the mass MHD according to [2.1.4]/[3.2.1] should beestablished based on a short voyage condition with 50% consumables witheven filling at scantling draft.

According to the provision of [2.1.1] maximum cargo mass Mh or Mhd should
be obtained from loading conditions at full scantling draft and with 50%
consumables. In general the maximum cargo mass (Mh) for an empty hold(Mh) corresponds to the cargo mass in homogeneous full condition at
scantling draft and with 50% consumables. Hence Mhd corresponds to thecargo mass in alternate loading condition at scantling draft and with 50%
consumables. Mfull is an artificial cargo mass and the maximum permissible
cargo mass for an empty cargo hold in connection with the determination ofhold mass curve. Unqoute We can not see that PT answered whether or notthese conditions should be based on “even filling at scantling draft.” Pleaseadvise.
In Ch 4, Sec 5, [4.1.1], the definition of pS and pW is not clear, there are twodifferent interpretations:653

4/5.4.1.1

CI

pS and pW

2009/3/3

1. the pS & pW is calculated at position TB at side shell, whatever is the value Interpretation 2 is correct.
of z
In order to clarify the requirement together with the clarification of the
2. the pS & pW is calculated at the exact value of z of the loading point where calculation point, we will consider the rule change proposal.
the bow pressure P_FB is to be estimatedWhat is the correct interpretation?

Page 20 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

662

Ref.

4/6.2.2.1

4/5.2.2.1 &
671
Table
4.5.4

Type

CI

RCP

Topic

Inertialpressure due
to liquid

Externalpressures on
exposeddecks

Datecompleted

Question/CI

Attachment

Answer

2008/5/28

CSR_JBP_Chapter4_Section6_[2.2.1] Inertial pressure due to liquid[Quote]When checking ballast water exchange operations by means of the flow
through method, the inertial pressure due to ballast water is not to beconsidered for local strength assessments and direct strength analysis.
[End quote]
Please consider the answer to question in KC ID 226.
Please be kindly requested to clarify that when the ship’s ballast water change
method is designed as flow through method, only hydrostatic water ballastpressure, regardless of inertial pressure, would be considered for local
strength check as per Chapter 6 and to carry out the direct strength analysis
as per Chapter 4_Appendix 2 (e.g. analysis of the transverse bulkhead underheavy ballast load condition).

2008/7/16

A separate definition of x (load point in the reference co-ordinate systemdefined in Ch.1, Sec.4) appropriate for pressures defined in Ch.4, Sec.5,
Table 4 is necessary.
External pressures on exposed decks (on hatch covers in Ch.9, Sec.5 as well)for load case H1, H2, F1 and F2 are calculated based on x/LLL where LLL is afreeboard length as defined in Ch.1, Sec.4, 3.2, while x is the X co-ordinate of
the load calculation point from the aft end of the scantling length L. The aftend (AE) in Ch.1, Sec.4, Figure 4 is relevant to the scantling length L only
We will consider the rule change proposal in order to be in line with IACS UR
despite the fact that positions of the aft end and fore end in L are not the
S21.
same as those in LLL.
It is therefore proposed that x in Table 4 is to read 'xLL' measured from the aftend of freeboard length LLL to be aligned with the text in the amended ILLC
or IACS UR S21, the origin of the requirement.
A background of this proposal is a sample calculation below indicating aconsiderable difference in pressures between CSR-BC and IACS UR S21.
For exposed deck in way of No.1 cargo hold of a capesize bulk carrier where
LLL=279.622 m, a=0.356.

1) x(from aft end of L)=250.787 m, pw=80.564 kN/m2 according to the current
CSR-BC Ch.4, Sec.5, 2.2.1.
2) x(from fore end of LLL=24.872 m, pw=85.028 kN/m2 according to IACS UR
S21,2. In this case x(from aft end of LLL)=254.750 m.
The difference in pressure exceeding 5% should not be ignored.

Page 21 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

673 4/3.2.2.2,
attc & 4/3.3.1.1

694
attc

4/5.4.1.1

716

Table
4/A.2.1

721

Chapter 4

Type

CI

Topic

Still Water
bending
moments

Bow flare
Question reinforcemen
t

CI

DSA

Question design loads

Datecompleted

Question/CI

Answer

Attachment

YY

2008/4/18

Please see attached Question

The assumed still water bending moments specified in Ch 4 Sec 3, 2.2.2 areused for strength check other than fatigue strength when the design still water
bending moments are not defined at the preliminary design stage. In this case,the coefficient fp should be taken as 1.0.
The assumed still water bending moments may be used for fatigue checkwhen the design still water bending moments are not defined at the
preliminary design stage.
In this case, the coefficient fp should be taken as 1.0 too, because the staticload components are independent of the probability of occurrence.
Therefore, our interpretation is given as follows.
In applying the requirement 2.2.2 of Ch 4 Sec 3, MWV,H and MWV,S arecalculated by 3.1.1 with fp=1.0.

2008/4/24

The bow flare reinforcement should be considered above the normal ballast
waterline in the fore part, with reference to the bow flare area pressure
regulated in Ch4 Sec5, 4.1.1
Just above the normal ballast waterline, the flare angle, alpha, may be
inclined inside as the attached sketch.
Please show how to treat the flare angle, alpha, in the case as above.

Reinforcements due to large dynamic pressures, caused by bow flare, areonly necessary, when the flare angle is positive. Large "flare loads" on the topof the bulbous bow are not physical possible.

2008/10/3

CSR_JBP_Chapter4_Appendix 2 Standard loading condition(e.g table1 No.5
load pattern) for DSA.
With respect to the ballast water load pattern ofthe deepest ballast condition, current rule gives one standard loading
pattern(e.g. load pattern No.5 in table 1), in which the upper wing tanker in
way of the middle cargo hold is fully filled but hopper tank and double bottomtank in way of the middle cargo hold are empty. However, in many actual
design practice, the wing ballast tank is normally connected to the hopper
ballast tank. In addition, the ballast tank is sometimes designed to cover two
cargo hold region. Therefore, there would be three loading pattern options for
DSA, as illustrated in attached document. Please kindly clarify or provide
common interpretation that, Which load pattern exactly is to be used for DSA?

The loading pattern 5 in Table 1 of Ch 4 Appendix 1 corresponds to therequirement of Ch 4 Sec 7 [3.2.3]. Where the topside water ballast tank isconnected to bilge hopper or double bottom water ballast tank or where theballast tanks are designed to cover two cargo hold region, the topside waterballast tank or the ballast tanks extended over two cargo hold region shouldbe empty in order to be empty with all double bottom tanks in way of cargohold being empty. In this case, the deepest ballast tank specified in theloading manual should be used.

2009/6/2

Rules for protected/non-watertight decks cannot be found. Please clarify the Presently, design loads for protected/non-watertight decks, including platform
design load for protected decks; platform decks in engine room or upper deck decks in engine room and upper deck under superstructure, are based onunder superstructure.
individual society Rules.

Page 22 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

736

741

747

Ref.

4/2.2.1.1

4/6.1.1.2

4/5.2

Type

CI

CI

Question

Topic

load
conditions

cargo
parameters

DSA

Date
completed

Question/CI

Attachment

Answer

2008/9/10

Chapter4_Sec2_[2.1.1] - GM & Kr value for others load conditions . The valueof GM and Kr will affect the roll motion and consequently affect the inertia
loads. Current CSR Bulk carrier rule only specify GM & Kr for three standard
load conditions (i.e. full load condition, normal ballast and heavy ballast).
The GM and k_R values as given in Table 1 are only preliminary values. The
However, regarding some load condition used for DSA (e.g.multiport load
scantlings and the approval have to be based on the actual values. For thecondition), there is no any specification in the rules on how to decide GM andpurpose to make an initial design, the designer has to choose preliminary
Kr for such conditions. It is found that CSR Tanker rules provide thevalues from his/her experience or from the mentioned table. In case of a multi
instruction for those non-standard load conditions as follows, "For optional
port loading condition you may use the GM and k_R values for full loadloading conditions with a mean draught other than the values defined, GM is
condition.
to be obtained by linear interpolation based on values for 0.6Tsc and
0.9Tsc."[JTP section 7/3.1.3.2] Please kindly advise how to calculate the kr& GM for those load conditions, which is not specified in the table 1 of
CH4_SEC2_[2.1.1], particularly for the multiport load condition.

2009/5/25

The last sentence in Ch.4, Sec.6,[1.1.2] reads:"For holds of non-cylindricalshape, and in case of prescriptive rule requirements, the upper surface of thebulk cargo may be taken at the upper deck level with a density of dry bulk
cargo equal to M/V_H.". Please clarify how to determine the parameters,h_HPU, B_H, h_0 when the cargo is loaded to the top of hatch coaming ,since those parameters are variable within the non-cylindrical holds.

For holds of non-cylindrical shape, only the last sentence in Ch.4 Sec.6 [1.1.2]
is applicable. In this case, cargo height (hc) is measured from the inner bottom
to upper deck level at the centerline of the mid hold and the density of the dry
bulk cargo is taken equal to max (1.0, M/VH), where M and VH are defined in“Symbol” in Ch 4 Sec 6. There is no need to define the parameters h_HPU,
B_H and h_0 since [1.1.1] is not applicable such holds.

Regarding Direct Strength Assessment (DSA) for cross deck, while loads oncross deck and hatch cover are stipulated in Ch.4, Sec.5-2, it is not clear how
to consider the load on cross deck from hatch cover through hatch end
coaming or stay. Hence it would be appreciated to clarify how to assess the
cross deck by DSA, considering load from hatch cover.

Normally, the strength of hatch cover and hatch coaming is evaluated by theprescriptive requirement and FEA using the loads thereon separately from thehold structures. Hence, the cargo hold FEA is carried out using the cargohold FE model excluding the hatch cover. This seems a practical way.
Therefore, in principle the wave loads on hatch cover need not be considered
for the cargo hold FEA. In addition, the cross deck structure is normallyassessed by the cargo hold FEA under the loading conditions specified in Ch
4 Appendix 2. However in case special cargoes are loaded on hatch coversuch as timber, etc., the strength of supporting deck structures in such aloading condition should be assessed appropriately

2008/9/10

Page 23 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

801

804

805

Ref.

Text
4/6.2.2.1

Text
4/6.2.2

4/6.3.3 &
7.3.4

Type

Question

Question

QuestionTopicinertialpressure

inertialpressurehigh density
cargo

Date
completed2009/6/19

2009/6/23

2009/1/24

Question/CI

Attachment

Answer

Ch4 Sec6, 2.2.1 requires that the inertial pressure due to ballast water is not
to be considered, when checking ballast water exchange operations by meansof the flow through method. With regard to the treatment of hydrodynamic
external pressure under such conditions, KC226 has interpreted thathydrodynamic external pressure should be considered. On assuming ballast
The approach described in KC 226 is still valid. Dynamic internal pressure is
exchange operations are normally carried out under calm sea condition, thenot explicitly defined but the internal static pressure pBS defined in Ch.4 Sec.6
inertial pressure due to ballast water is considered negligible, and then the[2.1.2] contains an overhead of 25 kN/m2 which covers the dynamic internalrequirement in Ch 4 Sec 6 [2.2.1] seems to be reasonable and practicable.
pressure of BWE operations by means of the flow through method. However,
However, the interpretation, which requires to consider hydrodynamic external this matter is relevant to harmonisation with CSR OT and will be submitted topressure corresponding to the probability level of 10^-8, seems to be
the harmonisation team.
excessive and inconsistent with the treatment of hydrodynamic internalpressure. Please reconsider the treatment of hydrodynamic external pressure
under ballast water exchange operations by means of the flow throughmethod.

A1: Local strength by Ch 6: checking of plating and ordinary stiffeners,
including buckling check, by using the prescriptive formulae defined in Ch 6,
all sections included.
fatigue check for longitudinal stiffeners by Ch 8: checking of fatigue at ends oflongitudinal stiffeners by using the simplified procedure defined in Ch 8, Sec 4.

In Ch 4, Sec 6, [2.2], the parameter (x-xB) in the definition of the inertialpressure pBW for load case H is taken equal to a default value for "local
strength by Ch 6" and for "fatigue check for longitudinal stiffeners by Ch 8".
Could you specify what is the meaning of "local strength by Ch 6" and "fatigue
check for longitudinal stiffeners by Ch 8"?
A2: For direct calculations, including buckling and fatigue, xB should be used
Could you also specify what value of the parameter should be used for "direct
as defined in Ch 4, Sec 6, [2.2] (i.e. X co-ordinate of the aft end ..., or of thecalculation (i.e. FEM)"?
fore end...) where the reference point B is defined in the same requirement by
the angle "phi" for load cases H1 and H2.

Regarding the mass of high density cargo used for strength check oftransversely corrugated watertight bulkheads in flooded condition, pleaseadvise on the following questions:
1) Ch.4 Sec.6 [3.3.4] & [3.3.5] refer hc. We understand hc should be
calculated according to either Ch.4 Sec.6 [1.1.1] or [1.1.2]. In case of nonhomogeneous loading conditions which should be the mass MHD or
MHD+0.1MH for BC-A ships?
2) In case of homogeneous loading conditions (e,g, homogeneous ore loading
conditions, etc.) which should be the mass MHD or MHD+0.1MH for BC-A
ships?
3) We understand for BC-B ships the mass should be MHD, of which pleaseconfirm.

The cargo mass to consider for flooding assessment of a BC-A in alternate is
MHD. The value of hc is then to be calculated with respect to the used cargodensity.
A2 : The cargo mass to consider for flooding assessment of a BC-A in
homogeneous is MH. The value of hc is then to be calculated with respect tothe used cargo density.
A3 : The cargo mass to consider for flooding assessment of a BC-B in
homogeneous is MH. The value of hc is then to be calculated with respect tothe used cargo density. As a "background", it is stated in S18 and now in CSR
BC Ch.4 Sec.6 [3.3.2] that the loading conditions to consider for flooding
assessment are those of the loading manual, i.e. "real conditions". The use of
MHD + 0.1 MH for a BC-A in alternate comes from UR S25 - now CSR BC
Ch.4 Sec.7 [3.4] and is only intended for design checks.

Page 24 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

818

Text
4/6.1.1.1

819

830

4/7.3.4.2

4/5.3.4.1

Type

Topic

Question

noncylindrical
hold

CI

Loading
conditions high density
cargo

Questionvertical
stiffeners

Datecompleted

Question/CI

Answer

2009/6/23

In Ch 4, Sec 6, [1.1.1], the distance hc is defined for cylindrical hold. The
determination of hc is not provided for hold completely filled when the cargohold is of non-cylindrical shape as it is provided for the requirement [1.1.2] atthe last paragraph.

For the determination of hc in Ch 4, Sec 6, [1.1.1] for holds of non-cylindricalshape and in case of prescriptive rule requirements, the upper surface of thebulk cargo may be taken at the upper deck level. We will consider acorrigenda to clarify this.

2009/9/8

The requirements 4/7.3.4.2 has the purpose to cover the most severe casewith high density cargo. In a case we faced the max cargo density was 3. The
compliance for this requirement was checked with density equal to 3.
However a worst case appeared for the upper part of the transverse Bhd withThis question and the draft answer you submitted will be considered in KCa smaller density (1.3) filling the cargo hold for the considered MHD+0.1 MH.
872 which has a larger scope.
In conclusion the proposed interpretation should be considered for being surethat all the most severest cases are covered by consideration of 2 extreme
cases: one with the highest density and the 2nd with the smallest density
corresponding to the filling of the cargo hold.

2009/3/10

Load calculation point for plating.
In case of vertical stiffeners, what is the load calculation point for plating? Is ita) the middle of the plate field, or b) the lower edge of the EPP or strake, as
described in Ch.6 Sec.1 [1.5.1]?

Attachment

Load calculation point for plating in case of vertical stiffener is the lower edgeof the EPP or strake, as described in Ch 6 Sec 1 [1.5.1]. We will consider aRule Change Proposal.

For the case of cargo loading as attached, the height of loaded cargo fromthe inner bottom to upper surface of cargo is calculated by as follows.

851
attc

4/6.1.1.2 &FigureQuestion
4.6.2

Ore cargosurface(smallamount ofmass)

2010/1/27

Ch.4 Sec.6 [1.1.2] defines the cargo surface when the cargo hold is notloaded up to the upper deck.
There are cases of cargo loading as attached which is differenet from Ch.4
Sec.6 Figure 2. It seems that the formulas of h_c, h_HPL, h_1 and h_2 are
not applicable.
Please advise the formulas to define the cargo surface and cargo height h_c
as well as V_TS in such cases

The section profile is to be as per the shaded area in the attached file,assuming the plane surface of width the parameter BH/2 in the centerline andthe inclined parts with an angle equal to psi/2. The profile is assumed tomaintain throughout the length of the cargo hold.
The virtual cargo section profile is to be determined so that the consequentcargo volume is equal to M/rho_c.
In calculating the cargo volume,1) the upper stool is to be disregarded,2) the volume of lower stool is to be deducted which is cut by the virtual
section profile.
Anyway, as the formula in [1.1.2] of Ch 4 Sec 6 is not used for the questioned
cases, we will consider a RCP in order to deal with such cases.

Page 25 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

859

860

873

Ref.

Type

Topic

Load
combinations
Interpretati
used for4/6.3.3.2
onchecking
bulkheadscantlings

4/6.2.2.1

Questionreferencepoint

Concentrated forces due
Interpretati
4/5.2.4.2
to unit loadon
on exposed
decks

Date
completed

Question/CI

Attachment

Answer

Reference is made to KC#402
Questions related to interpretation of the following sentence in Ch.4 Sec.6
3.3.2
Please advise the interpretation of following sentence.
"The most severe combinations of cargo induced loads and flooding loads areto be used for the check of scantlings of each bulkhead, depending on theloading conditions included in the loading manual."
2010/2/15

In ship with BC-A notation, most of ships may be intended to carry, in nonhomogeneous condition, the dry cargo in bulk with density between 0.9 and3.0. We have examined the strength of corrugate BHD according to URS18
and Ch.4. Sec.6 3.3.3. The most severe case is the flooded nonhomogeneous condition with the cargo density of 1.78 t/m3. If the loading
manual does not include the condition with the density 1.78t/m3, the case of
1.78ton/m3 is considered or not? And if the corrugated bulkhead with density
1.78 t/m3 is not considered, the ship have the limitation about the cargo withdensity 1.78 t/m3?
Please clarify!!!

This question will be considered together with KC 872. A Common
Interpretation will be made to clarify applicable loads, density and angle ofrepose for intact, flooded and fatigue condition.

2009/1/24

In CSR-BC Ch 4, Sec 6, [2.2.1], there are two possible methods for thedetermination of the reference point B for load cases R and P: - the first one isdefined through the definition of yB and zB and the figure 3, - the second one
is defined as being the upper most point after rotation by the angle "phi". For
The interpretation is correct: only the second method (B being the upper mostsome geometries of the ship section considered, in particular depending on
point after rotation by the angle "phi"). It should be applied for local strength,
the angle of the sloping top side tank plate or when the deck is not horizontal,
direct strength and fatigue check.
the point B obtained through the two methods are different. Our interpretationis that only the second method (B being the upper most point after rotation by
the angle "phi") should be applied as it is the most physical and it is a general
method. Please confirm our interpretation?

2010/8/6

Ch4 Sec5, 2.4.2 requires concentrated force due to unit load. However, thescantling determination procedure of the structure, which is loaded with thisconcentrated force, is not clearly indicated in CSR.
Please confirm the procedure to determine the scantling of following members
in cases where a unit load is carried on an exposed deck;
1. Plating
2. Stiffeners
3. Primary supporting members, including the cases that direct strength
assessment in Ch7 applies.

The structural member under heavy concentrated load should be adequately
stiffened by local support in general, and its scantling, which is to be based on
the net scantling approach according to Ch3, Sec2, is at the discretion of theSociety.
This issue will be considered in the Harmonization of the two Common
Structural Rules.

Page 26 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

888

902

Ref.

Table
4A.2.54/3.2.2,
4/3.2.3 &4/3.2.4

Typequestion

RCP

Topic

FEA

margins of
SWBM &SWSF

Datecompleted2009/6/23

2009/7/16

Question/CI

Attachment

Answer

Ch4 App2, Table5 defines load cases to be analyzed in FEA. The cases
Nos.12 to 15 are in harbour conditions and their still water bending moment
are indicated as M_S,P(+) and M_S,P(-). On the other hand, Note b) of
We confirm your comment and will make an editorial correction in the Rules toTable5 specifies M_SW,P,H and M_SW,P,S as allowable still water bending
replace M_S,P(+) and M_S,P(-) by M_SW,P,H and M_SW,P,S so as to in line
moment for harbour condition. It seems that M_S,P(+) and M_S,P(-) arewith the other tables and the Note b).
identical to M_SW,P,H and M_SW,P,S respectively. Please confirm the above
and correct these discrepancies.

Since scantling approval is based on the hull girder bending moment andshear force values contained in the preliminary loading manual, which may besubject to change (and possibly be higher) in the final loading manual. It isbelieved that the CSR Tanker guidance notes recommending that duringinitial design a margin be placed on the Still Water Bending Moment and Still
Water Shear Force is a very good provision in the rules and that similar
guidance notes be contained in the CSR Bulk Carrier Rules. Reference ismade to CSR Tanker Sec.7, 2.1.1.6 and Sec.7, 2.1.3.6, which are as follows:
Guidance note: It is recommended that, for initial design, the permissible hull
girder hogging and sagging still water bending moment envelopes are at least
5% above the hull girder still water bending moment envelope from theloading conditions in the loading manual, to account for growth and design
The definition of the margins to be applied on the hull girder bending moment,
margins during the design and construction phase of the ship.
shear force... is the responsibility of the designer at each step of its project.
Rules are to be applied on the values given by the designer.
This subject will also be submitted to the harmonisation team.

Guidance note: It is recommended that, for initial design, the permissible hull
girder still water shear force envelopes are at least 10% above the hull girder
shear force envelope from the loading conditions in the loading manual, toaccount for growth and design margins during the design and construction
phase of the ship.
It is believed that like guidance notes for margin on bending moment andshear force values should be included in CSR Bulk Carriers for application
during initial design both for values in intact and flooded condition. It isbelieved that the values of margins that are applied to Tankers would also beappropriate for Bulk Carriers.

Page 27 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

907 4/6.1.1.2 &attc 4/6.1.1.1

910

912

913

Tables
4.A2.1 &4.A2.3

4/6.

4/6.

Type

Q&A

Question

Topic

Internalpressures &forcesappliedduring FEM
analysis

Loading
condition
accelerations

RCP

sloshingpressure

RCP

min pressure
for decks inER

Datecompleted2010/4/14

Question/CI

Please see the attached PDF file containing 2 questions about CSR for bulk
carrier in Chapter 4 section 6 Internal Pressures and Forces when applying
them in the FEM analysis.

Attachment

AnswerQ1a)Static cargo pressure at Pos 1 and Pos 2 are not the same, since the shapeof cargo gives a reduced hc outside Bh/4 from centerline. In your example thestatic pressure will be pCS = ρC x g x KC (ha + hDB − z).
b)At your position 4 the cargo pressure will be zeroc)In your example pCS = ρC x g x KC (hb + hDB − z) should be used.
d)In your example hd should be used.
YQ2a)For calculation of hc, psi does not need to be considered because anequivalent horizontal surface is assumed.
Static pressure at top side plate is to be zero since Kc is defined to be zero for
top side plate, upper deck and sloped upper stool.
b)In your example the static cargo pressure is the same in region 1 and 2.
c)In your example hc should be used.

2009/9/4

Loading condition No 1 considers homogeneous loaded cargo. According toNote 2 a density of 3t/m has to be used. Please confirm that GM and k_R of
LC1 is a homogeneous loading condition with a density of 3.0 t/m3 which has
the real homogeneous loading condition (density << 3t/m) has to be used in
to be included into the loading manual. The corresponding calculated values
this context and not a higher GM value, which considers the lower COG of thisof GM and kr have to be used in FEM analysis and not those of a loading
theoretical cargo. From our point of view the aim of this loading condition is tocondition with a lower density. If these values are not available, default values
create maximum sea pressure at side shell without counterpressure due tohave to be used as per Ch.4 Sec.2 tab.1.
cargo. Higher accelerations, based on the theoretical density of 3t/m, need not
to be considered.

2009/9/4

Minimum pressures for ballast tanks Please consider including minimum
sloshing pressures for ballast tanks, similar to CSR Tanker 7/4.2.4.

Bulker CSR does not have the structural scantling formula according tosloshing pressure for ballast tanks. To include design pressure and scantling
formula for sloshing, sufficient ramification study should be carried out. It will
be discussed during harmonization process with considering the necessity ofsloshing estimation in ballast tanks of bulkers.

2009/7/16

Minimum pressure for platform decks in engine room.
Please consider including minimum pressure for platform decks in engine
rooms, similar to CSR Tanker 7/2.2.4.

A minimum thickness is currently required for platform plating in the engine
room.
As this differs from the CSR OT approach, this will be submitted to theharmonisation team.

Page 28 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

937

Ref.

4/8.2.2.2 &4/8.5.1.3

Type

CI

Topic

Short voyage
loading
conditions

Datecompleted

Question/CI

Answer

2010/4/9

Reference is made to Chapter 4, Section 8, 2.2.2 and 5.1.3.
1) Does short voyage condition have to be considered on a mandatory basis?
2) If the submitted Loading Manual does not include short voyage condition is
it to be included in the Loading Manual?
In KC ID 492, the reply is:where a short voyage alternate loading condition with more severe filling thanthe minimum loading condition in [2.1.1] and [2.1.4] is specified in the loading
manual, strength check for such more severe loading condition should be
carried out in accordance with the CSR requirements.
Please clarify?

A1)
Short voyage condition is not a mandatory basis. If the ship is not intended tomake such voyage, it is not relevant to add it to the loading manual.
As a consequence, the ship will not be able later on to practice short voyages
with more severe loading conditions than those described in the loading
manual.
A2)
Ch.4 Sec.8 [2.2.2] gives an extensive list of loading conditions to beconsidered when they are pertinent.
Thus if short voyages are not envisaged for the ship, they need not be
included in the loading manual.
A corrigendum will be issued on Ch.4 Sec.8 [2.2.2] and [5.1.3].

Attachment

Page 29 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

Type

Topic

Date
completed

Question/CI

Attachment

AnswerPlease advise the answer to the question on the design with the following
Table
non-homogeneous loading conditions in the loading manual:
4.6.1, Text
Design with- cargo density is 3.0 and cargo hold is not loaded up to upper deck,
4/6.3.3.2,
non- cargo density is lighter than 1.78 (for instance 1.7) and cargo hold is loaded
963 6/1.3.2.1, Question homogeneou 2009/12/16
This question is considered together with KC 851, 859 and 972
up to upper deck.
6/1.3.2.3,
s loading
For this design is local strength check required for intact condition and flooded
6/2.3.2.3 &condition
condition for the above loading conditions according to Ch.6 Sec.1 [3.2.1] &6/2.3.2.6[3.2.3] and Ch.6 Sec.2 [3.2.3] & [3.2.6] (or [3.6] by RCN1-8)?

964

983

4/6, 4/7 &
4/8

4/3.

CI

Cargo
density limits
for BC-A and
BC-B ships

Question

Longitudinalstrengthcheck atfloodedcondition

2010/6/29

For BC-A and BC-B ships, there is a design loading condition in Ch 4, Sec 7,[2.1] requiring maximum draught with cargo density 3 t/m3. On the other hand
there are cargoes which have density higher than 3t/m3. We would like tohave interpretations on the two following questions:a) Is a limit in cargo density of 3t/m3 clearly stated in CSR-BC?
b) In case of loading conditions within the loading manual having density
higher than 3t/m3, are they specific checks to carry out in addition of thosecorresponding to 3t/m3?

a)The cargo density of 3.0 t/m3 is required as design basis for BC-B and BC-A
vessels as stated in Ch.4 Sec.7 [1.2] and [2.1]. Based on the design loading
conditions according to Sec.7, hold mass curves will be created according to
Sec.8 which will control the loading and unloading of the vessel in operation.
There is no limitation on cargo density in operation unless additional feature
notation {maximum cargo density x.y t/m3} specifies the maximum cargodensity less then 3.0 t/.m3.
b)If specific cases (with high density or no) are requested by the Owner, thosecases can be included in the Loading Manual and those cases should bespecifiquely studied (on a case by case basis).

2010/3/16

The query is regarding Chapter 4- Section 3 of CSR for Bulk Carriers, i.e.
Longitudinal Strength Check at Flooded condition.
1. Do we have to assume structural damage to the Hull in this case?
2. Or, is it the water ingress from the deck through the Hatch?
3. Please explain if we have to consider the damage from side or the water
ingress from top, which results only in hold flooding.

For Ch.4 Sec3, Longitudinal Strength Check at Flooded condition, water
ingress of the cargo hold is assumed without any structural damage or filling ofadjacent compartments.

Page 30 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

987
attc

Ref.

4/7.3.6.1&
3, Fig4.A1.1

Type

RCP

Topic

Harbourmass curves
for BC-A
loaded holds

Datecompleted2010/3/16

Question/CI

Attachment

AnswerWe have found that the CSR-BC is unclear about how to construct the mass
curve for the harbour condition for loaded holds.
Please refer to the attached sketch.
Ch 4, Sect 7, 3.6.1 results in line 1 (red).
Ch 4, Sect 7, 3.6.3 results in line 2 (blue).
Depending on the geometry of the vessel, Ch 4, Sect 7, 3.6.3 may result inline 3 (green).
Ch.4 Sec.7 [3.6.1] and [3.6.3] are both valid and acceptable hence the final
Ch 4, Appendix 1, Figure 1 (a) results in line 4 (black).
curve (upper limit) should be larger of the two curves. We agree that Fig.1 (a)Various arguments can be made to support the construction of each line.
should be corrected as suggested (Line 2) based on [3.6.3].
Line 1 comes from a load condition that has been analysed for the design andis therefore well supported.
Lines 2 and 3 are based on a simple empirical formula within the Rules. We
are not aware of cases of double bottom failure within harbour for UR S25
ships, hence the empirical formula appears valid. However, where the vesselgeometry produces line 3, rather than line 2, their would be a good case forincreasing the harbour maximum to line 1, which is verified by calculation.

Line 4 is not backed by text in Ch 4, Sect 7 and I suggest that the labelling ofAppendix 1, Figure 1 (a) is incorrect and that the brackets should be removed
so that “1.15(MHD+0.1MH)” becomes “1.15MHD+0.1MH”.
Could this please be investigated with a view to IACS placing an interpretationon the Knowledge Centre and/or issuing a Rule Corrigenda item.
Please also note this should be considered in conjunction with KC item 633
which is under study by IACS.

995

4/5.2.1.1

CI

FE cargohold model weather
loads

2010/5/7

Ch. 4, Sec. 5, Para. 2.1.1 states: "The external pressures on exposed decks
are to be applied for the LOCAL SCANTLING CHECK of the structures on
exposed deck but -----" This is under Para. 2.1 "General" and, therefore, Para.
2.2 Load cases H1, H2, F1 and F2" and Para. 2.3 "Load cases R1, R2, P1
and P2" are controlled by Para. 2.1. In addition, the weather loads require tobe applied to the structures on exposed deck only. Please clarify if theweather loads need to be applied to the FE cargo hold model or not?

Yes, the weather loads shall be applied to FE cargo hold model. In order toclarify the Rules, the relevant paragraph is suggested to be modified as “Theexternal pressures on exposed decks are to be applied for the scantling checkof the structures on exposed deck but not applied for fatigue strength
assessment." (local removed from the sentence)
This will be done in the next Corrigenda.

Page 31 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

1023
attc

Ref.

4/6.1.1.1

Type

RCP

Topic

Definition of
the dry cargo
uppersurfaceDatecompleted

Question/CI

Chapter4_CSR-BC_Sec6_[1.1.1]The definition of the dry bulk cargo uppersurface.
It is specified in Ch4/6/1.1.1 of CSR Bulk Carrier that ” When the dry bulk
cargo density is such that the cargo hold is loaded to the top of hatchcoaming, the upper surface of the dry bulk cargo is an equivalent horizontal
surface to be determined in considering the same loaded cargo volume in theconsidered hold bounded by the side shell or inner hull, as the case may be.”2010/6/29
Regarding the above definition of “the hold bounded by the side shell or innerhull", it seems not very precise and might cause some misunderstandings.
Take a typical dry bulk cargo hold for example, three different possible
boundary definitions marked in red as shown in the attached graphic
illustration might be some possible understandings.
Two optional proposals for the revision are as below.

Attachment

Answer

The Figure 2 in your attachment is correct.
In order to describe the equivalent horizontal surface more clearly, acorrigenda is to be carried out.
The first paragraph is to be modified as following:
When the dry bulk cargo density is such that the cargo hold is loaded to the
top of hatch coaming, the upper surface of the dry bulk cargo is to be taken as
an equivalent horizontal surface determined by considering the same cargovolume loaded in to a cargo hold with boundaries formed by inner bottom,
hopper if any, and side shell for single side skin or inner side for double side
skin.

Y

Figure 1 in Ch4/Sec6 will be modified accordingly to illustrate the boundary
definition

1) “When the dry bulk cargo density is such that the cargo hold is loaded tothe top of hatch coaming, the upper surface of the dry bulk cargo is anequivalent horizontal surface to be determined in considering the same loadedcargo volume above the lower intersection of topside tank and side shell or
inner side in the considered hold bounded by the side shell or inner hull.”
2) “When the dry bulk cargo density is such that the cargo hold is loaded tothe top of hatch coaming, the upper surface of the dry bulk cargo is to betaken as an equivalent horizontal surface determined by considering the samecargo volume loaded in to a cargo hold with vertical boundaries formed by thetransverse bulkheads and side shell or inner side. The spaces occupied by
the topside tanks and the upper bulkhead stool should be considered as partof the cargo hold space in the determination of this equivalent horizontal
surface.

1025
attc

4/6.1.1.1

CI

Hc value ofdry bulk
cargo in fullfilledcondition

2010/5/17

Chapter4_CSR-BC_Sec6_[1.1.1] Hc value of the dry bulk cargo in full-filledcondition Regarding the hc value for cargo hold being loaded up to the top of
hatch coaming: Ch4/Sec6/1.1.1 specifies the procedure of calculating theheight of dry cargo upper surface. Meanwhile a formula for calculating the hc
For holds of cylindrical shape, the volume of upper stool is ignored when hC isvalue is given specifically for holds of cylindrical shape.
calculated by the formula in Ch.4 Sec.6 [1.1.1].
Question: For a typical bulk carrier, upper stools are generally arranged in the
cargo hold. Obviously, the hc value should be different by using the above twoprocedures. Which procedure should be used? In other words, should thecargo hold with upper stools be considered as one of cylindrical shape or not?

Page 32 of 34

YIACS Common Structural Rules Knowledge Centre

KCID
No.

1026

Ref.

4/3.3.1.3

Table1042 4/A2.1,2,3,
4,5,6

1047

4/7.2.1.1

Type

Topic

CI

Wave
inducedbending
moment(0.4Mw) fortarget BM in
harbourcondition

RCP

CI

Loading
conditions to
be includedin Trim &Stability
bookletMax cargomass incargo holds
at maxdraught
conditionwith 50% ofconsumables

Datecompleted2010/5/12

Question/CI

Chapter4_CSR-BC_Sec3_[3.1.3] Wave-induced bending moment(0.4Mw) fortarget BM in harbor condition
It is specified in Ch4/3/3.1.3 of CSR Bulk Carrier that the vertical wave
bending moment Mwv,p in harbour condition equals to 0.4Mwv. It is notclearly specified whether 0.4Mwv should be included in the target bending
moment in harbour condition for direct strength analysis.

Attachment

Answer

The wave-induced bending moment 0.4Mwv should be included in the target
bending moment in harbour condition for direct strength analysis.
This will be specified in the next corrigenda.

Please be kindly requested to provide clarification

2010/6/29

We do not consider the "standard loading condition for direct strength
analysis" listed under Appendix 2 of CH4 is required to be included in the Trim
& Stability booklet.
For example, for LC No.6 "Multi Port-3" in Table 1 in Ch.4 Appendix 2, thedesign value of the sagging bending moment will become quite large if animaginary loading condition is prepared on purpose to realize the condition
corresponding to LC6. Thus, we would say it is not so reasonable in practice
to include such an imaginary loading condition in the Trim & Stability booklet.

We agree to your comment that loading conditions indicated in Appendix 2 in
Ch.4 are not required to be included in the Trim & Stability booklet.
The loading conditions applicable for loading manual is specified in Chapter 4
Section 7 and 8.

Would you have any further question, please don't hesitate to contact the
In order to avoid unnecessary argument between Class & Builder, we suggest IACS Permanent Secretariat.
that the additional statement should be provided which specifies that it is not
required to prepare the loading conditions to realize the LCs indicated in the
Appendix 2 and that such loading conditions need not to be included in the
Trim & Stability booklet.

2010/5/12

In Ch.4 Sec.7 [2.1.1] is written: "For the determination of the maximum cargomass in cargo holds, the condition corresponding to the ship being loaded at
maximum draught with 50% of consumables is to be considered."Is this defined for the short voyage conditions?

Ch.4 Sec.7 [2.1.1] defines the upper limit for the cargo mass in holds, i.e. thepay load, by considering only 50% of consumables at full draught. This has
not to be considered as a mandatory design loading condition.
This definition of the upper limit is not to be confused with definitions of shortvoyage conditions.

Page 33 of 34

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

1054
4/6.1.1.1
attc

Type

Topic

Hc value ofdry bulk
cargo in fullInterpretati
filledoncondition(Ref to KC ID
1025)

Date
completed2010/8/11

Question/CI

Attachment

AnswerWith reference to KC ID 1025, it seems that the answer do not fully cover ourquestions. It is true that the formula should be used to calculate hc for holds ofcylindrical shape. However, our question is "Should we consider the cargohold with upper stools as one of cylindrical shape or not?".
Most of CSR PT3 members assume that cylindrical shape means that a cargo
is longitudinally cylindrical along its entire length and no upper stools should
be arranged. For a typical bulk carrier with upper stools, our calculation shows Yes, we consider a cargo hold as having a cylindrical shape if it maintains athat the two methods in Ch4/Sec6/1.1.1 of CSR-BC will result in different hc
cross sectional shape over the hold length with or without upper stools.
values.
Therefore, we are expecting an answer of Yes or No with explanations to thequestion "should the cargo hold with upper stools be considered as one ofcylindrical shape?". If Yes, the explanations are expected. If No, clear
statements of the rule may be needed. Detailed calculation procedure is
attached.

Page 34 of 34

YKC#283
Design still water bending moments in CSR Bulk rules.
Ch.4 Sec.3 [2.2.1] and [2.2.2] and Ch.5 Sec.1 [4.2.1], [4.2.2], [4.2.4] and [4.3.1]
We assume the following interpretation is valid for design bending moments in intact
condition:

1. Rule minimum (Zmin.)2. Envelope for design
loading conditions

3. Envelope for loading
manual/instrument

Alt 2

3. Envelope for loading
manual/instrument

1(blue). Rule minimum Z (section modulus) is maintained within 0.4 L amidships
according to Ch 5 Sec 1 [4.2.1] and [4.2.4]. Corresponding bending moments are given as
preliminary design moments in Ch 4 Sec 3 [2.2.2].
2(green). Envelope curve for all loading conditions in the loading manual. For somepoints this may exceed the rule minimum requirement (ref. Ch.4 Sec.3 [2.2.1] and Ch.5
Sec.1 [4.2.2] and [4.3.1]).
3(red).
Envelope (permissible) curve for loading manual/instrument.
Q1: As long as the item 1 is satisfied, i.e., Rule min. Z is maintained within 0.4L amidships,
could “Alt 2” below be used as Envelope for the loading manual/instrument? Could “Alt 2”
be used for sig-x for local scantlings and for design bending moment for FEM calculation?
Note that the red line may have an uneven distribution within 0.4L amidships and might bebelow rule minimum (item 1 above).

Q2: In this connection, please clarify if Ch.4 Sec.3 [2.2.2] is a minimum requirement within
0.4L amidships or just a guidance. If it is not a rule minimum, and in case the Envelope (line2) is below Min. Z (line 1), hull girder capacity of min Z is not fully utilised by thedesign/permissible still water bending moments of the vessel. As far as we understand, this isgiven as a minimum requirement for design still water bending moment in the CSR-Tanker
rules. Please clarify.
Q3: For the flooding condition, we assume the following relationship. We assume that thesame principle also applies to harbour condition. Please confirm if our assumptions arecorrect.
20%MW

1. Intact envelope
2. Intact envelope + 20%MWV
3. Flooding envelope fromflooding of design conditions

4. Envelope for loading
manual/instrument

1. The intact bending moment based on above assumptions.
2. The Intact envelope + 20%MVW
3. The envelope curves from flooding of design loading conditions. This curve exceed
curve 2 for certain points.
4. Design limit for the flooding condition and envelope curve for loading
manual/instrument.

KC#465

KC#485Q
Table 2 of Chapter 4 section 4: Reference hull girder loads and motions of ship

weather weather weather weather weather weather weather weather
side
side
side
side
side
side
side
side
(port)(stbd)(port)(stbd)(port)(stbd)(port)(stbd)

Vert.BM& SF
Hor.BM
Heave
Pitch

R1
-

R1
-

R2
-

R2
-

P1
Yes

P1
Yes

P2
Yes

P2
Yes

Yes
Down
Stbd up

Yes
Down
Stbd
down

Yes
Up
Stbd
down

Yes
Up
Stbd
up

Down
Stbd up

Down
Stbd
down

Up
Stbd
down

Up
Stbd
up

-

-

-

-

Port

Stbd

Stbd

Port

Roll
Surge
Sway

Table 3 of Chapter 4 section 4: Load combination factors

weather side
(port)

weather side(stbd)

weather side
(port)

weather side(stbd)

weatherside (port)

weatherside (stbd)

weatherside (port)

weatherside (stbd)

R1

R1

R2

R2

P1

P1

P2

P2

asurgeax apicth
g sin
asway
ay arollg sinaheave Sqrt(L)/40
az

aroll
apitch

0
0
0
0
1
1

0
0
0
0
-1
-1
Sqrt(L)/40

1
0

-1
0

0
0
0
0
0
0
0
0
-1
1
-1
1
- Sqrt(L)/40- SQRT(L)/40
-1
0

1
0

0
0
0
1
0.3
0.3
1

0
0
0
-1
-0.3
-0.3
1

0
0
0
-1
-0.3
-0.3
-1

0
0
0
1
0.3
0.3
-1

0.3
0

-0.3
0

-0.3
0

0.3
0

Figure 3 of Chapter 4, section 6: Definition of Xb, Yb

KC#485A

Load case

Load Case and load combination factors for all wave directions

H1

H2

F1

Table 1:

Definition of load cases

F2

R1

R2

P1

P2

EDW

“H”

“F”

“R”

“P”

Heading

Head

FollowBeam

Beam

Max Bending Moment

Max. roll

Max Ext. Pressure

Max Bending
MomentEffectSagging

Load case

Hogging

H1

H2

Sagging

Hogging)

(+)

(-)

(+)

(-)

Table 2:

Reference hull girder loads and motions of ship

F1

F2

R1

R2

P1

P2

Vert. BM & SF

Yes

Yes

-

Yes

Hor. BM

-

-

Yes

-

Wave Direction

Head

Follow

R1

R2

P1

P2
Yes

Yes

Port

S’board

Heave

Down

Up

-

-

Down

Up

Down

Up

Down

Up

Down

Up

Pitch

Bow down

Bow up

-

-

-

-

-

-

-

-

-

-

Roll

-

-

-

-

Stbd up

Stbd down

Stbd up

Stbd down

Port up

Port down

Port up

Port down

Surge

Bow

Bow

-

-

-

-

-

-

-

-

-

-

Sway

-

-

-

-

-

-

Port

Port

-

-

S’boardS’board

Weather side and ship
motion in beam sea

Table 3:

LCF

H1

F1

Head

Wave Direction

1)

H2

F2

Load combination factors LCF

R1

R2

Follow

P1

P2

R1

R2

Port

P1

P2

S’board

MWV

CWV

-1

1

-1

1

0

0

0,4 

TLC
T

TLC
 0,4
T

0

0

0,4 

TLC
T

TLC
 0,4
T

QWV

CQW*

-1

1

-1

1

0

0

0,4 

TLC
T

TLC
 0,4
T

0

0

0,4 

TLC
T

TLC
 0,4
T

MWH

CWH

0

0

0

0

1,2 

asurge

CXS

-0.8

0.8

0

0

apitch x

CXP

1

-1

0

gsin)

CXG

1

-1

asway

CYS

0

aroll y

CYR

gsinT

CYG

aheaveCZHaroll zCZR

0apitch z

CZP

1Note * The LCF for CQW

0,6

TLC
 1,2
T

0

0

TLC
 1,2
T

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

1

0

0

L
40

0

0

0

-1

0

0

TLC
T

 0,6

TLC
T

is only used for the aft part of midship section.

TLC
T

1,2 

TLC
T

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

-1

0

0

-1

1

-1

0.3

-0.3

-1

1

-0.3

0.3

-1

0.3

-0.3

-1

1

-0.3

0.3

L
40

1

-1

L
40

L
40

1

-1

1

-1

0.3

-0.3

-1

1

-0.3

0.3

0

0

0

0

0

0

0

0



The inverse value of it should be used for the forward part of the midship section.

KC#515

CSR_BC
Chapter 4, Appendix 1
3.1.2 BC-A ships
The maximum permissible cargo mass ( Wmax (Ti ) ) and the minimum required cargo mass ( Wmin (Ti ) )for the adjacent two holds at various draughts ( T i ) are determined, in t, by the following formulae:

Wmax (Ti )2( M Full orM HD )  0.1M H , whichever is the greater for Ts t Ti t 0.67Ts……
There are two sets of data M Full , M HD and M H in the two adjacent cargo holds. The result values
are different significantly especially at fore end and aft end cargo holds. Which data shall be applied in
the formula?
The formula is proposed to be modified as follows:

Wmax (Ti )M Full , fwd᧧M Full ,aft

Wmax (Ti )M HD , fwd  M HD ,aft  0.1( M H , fwd  M H ,aft ) / 2 , whichever is the greater for
Ts t Ti t 0.67Ts

M Full , fwd , M HD , fwd , M H , fwd : M Full , M HD , M H in one cargo hold.
M Full ,aft , M HD , aft , M H ,aft : M Full , M HD , M H in adjacent cargo hold.

KC#571
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j[SGhZSGyGXPGtoGV}oG
toGaG{GGGGG
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KC#627

KC#633
Chapter 4, Appendix 1

Common Structural Rules for Bulk Carriers

Appendix 1 – HOLD MASS CURVES
Symbolsh: Vertical distance from the top of inner bottom plating to upper deck plating at the ship’s centreline, in m.

MH: As defined in Ch 4, Sec 7

MFull: As defined in Ch 4, Sec 7

MHD: As defined in Ch 4, Sec 7

MD: The maximum cargo mass given for each cargo hold, in t

Mblk

: The maximum cargo mass in a cargo hold according to the block loading condition in the loading manual,
in t

THB

: As defined in Ch 4, Sec 7

Ti: Draught in loading condition No. i, at mid-hold position of cargo hold length "H , in m

VH

: As defined in Ch 4, Sec 6

Vf and Va: Volume of the forward and after cargo hold excluding volume of the hatchway part, in m3.

: The sum of mass in forward and after holds

1. General
1.1 Application
1.1.1
The requirements of this Appendix apply to ships of 150 m in length L and above.
1.1.2
This Appendix describes the procedure to be used for determination of:x

the maximum and minimum mass of cargo in each cargo hold as a function of the draught at mid-hold positionof cargo holdx

the maximum and minimum mass of cargo in any two adjacent holds as a function of the mean draught in wayof these holds.

1.1.3
Results of these calculations are to be included in the reviewed loading manual which has also to indicate themaximum permissible mass of cargo at scantling draught in each hold or in any two adjacent holds, as obtained fromthe design review.
1.1.4
The following notice on referring to the maximum permissible and the minimum required mass of cargo is to be
described in loading manual.
Where ship engages in a service to carry such hot coils or heavy cargoes that have some adverse effect on the local
strength of the double bottom and that the loading is not described as cargo in loading manual, the maximum
permissible and the minimum required mass of cargo are to be considered specially.

Page 56January 2006

Common Structural Rules for Bulk Carriers

Chapter 4, Appendix 1

2. Maximum and minimum masses of cargo in each hold
2.1 Maximum permissible mass and minimum required masses of single cargohold in seagoing condition
2.1.1 General
The cargo mass curves of single cargo hold in seagoing condition are defined in [2.1.2] to [2.1.5]. However if theship structure is checked for more severe loading conditions than the ones considered in Ch 4, Sec 7, [3.7.1], theminimum required cargo mass and the maximum allowable cargo mass can be based on those corresponding loading
conditions.
2.1.2 BC-A shipx

For loaded holds
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following
formulae:
Wmax (TS )M HD  0.1M H

Wmax (Ti )M HD  0.1M H  1.025V H

TS  TihHowever, Wmax (Ti ) is no case to be greater than MHD.
The minimum required cargo mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following
formulae:
Wmin (Ti )for Ti d 0.83TS

0Wmin (Ti ) 1.025VH

Ti  0.83TShfor TS t Ti ! 0.83TS

The maximum permissible mass (Wmax (Ti )) at various draughts (Ti) in harbor condition should also bechecked by the following formulae in addition to the requirements in [2.2.2]:x

Wmax (Ti )M HD

Wmax (Ti )M HD  1.025VH

for

0.67TS  TihTi t 0.67TS

for Ti  0.67TS

For empty holds which can be empty at the maximum draught
The maximum permissible mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following
formulae:
Wmax (Ti )M FullWmax (Ti )M Full  1.025VH

for TS t Ti t 0.67TS
0.67TS  Ti
hfor Ti  0.67TS

The minimum required mass ( Wmin (Ti ) ) is obtained, in t, by the following formula:
Wmin (Ti )0for Ti d TS

Examples for mass curve of loaded cargo hold and cargo hold which can be empty at the maximum draught for BCA ships are shown in Fig 1.

January 2006

Page 57

Chapter 4, Appendix 1

Common Structural Rules for Bulk Carriers

1.15MFull
MFull

Cargo mass

Harbour

Seagoing

0(a) Loaded hold
Figure 1:

0.67TSTS

Draught(b) Cargo hold which can be empty at the maximum draught
Example of mass curve for BC-A ships, without {No MP}

2.1.3 BC-A ship with {No MP}x

For loaded holds
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is the same specified in [2.1.2].
The minimum required mass ( Wmin (Ti ) ) is obtained, in t, by the lesser of the following formulae:
Wmin (Ti )for Ti d T HB

0Wmin (Ti ) 1.025VH

Ti  THB
for TS t Ti ! T HBhorWmin (Ti )0.5M H  1.025VH

TS  Tihfor TS t Ti

Wmin (Ti ) t 0x

For empty hold which can be empty at the maximum draught
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formula:

Wmax (Ti )M Full  1.025V H

TS  Tih

The minimum required mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formula:

Wmin (Ti ) 0

for

Ti d TS

The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) in harbor condition should also bechecked by the following formulae in addition to the requirements in [2.2.2]:
Wmax (Ti )M FullWmax (Ti )M Full  1.025VH

Page 58

for TS t Ti t 0.67TS
0.67TS  Ti
hfor Ti  0.67TS

January 2006

Common Structural Rules for Bulk Carriers

Chapter 4, Appendix 1

Examples for mass curve of cargo hold for BC-A, {No MP} ships are shown in Fig 2.

(a) Loaded hold
Figure 2:(b) Cargo hold which can be empty at the maximum draught
Example of mass curve for BC-A ships, {No MP}

2.1.4 BC-B and BC-C ships
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formulae:
for TS t Ti t 0.67TS

Wmax (Ti )M FullWmax (Ti )M Full  1.025VH

0.67TS  Ti
hfor Ti  0.67TS

The minimum required cargo mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formulae:
Wmin (Ti )for Ti d 0.83TS

0Wmin (Ti ) 1.025VH

Ti  0.83TShfor TS t Ti ! 0.83TS

2.1.5 BC-B and BC-C ships with {No MP}
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formula:

M Full  1.025V H

Wmax (Ti )TS  Tih

The minimum required mass ( Wmin (Ti ) ) is obtained, in t, by the lesser of the following formulae:
Wmin (Ti )for Ti d THB

0Wmin (Ti ) 1.025VH

Ti  THBhfor TS t Ti ! THB

orWmin (Ti )0.5M H  1.025VH

TS  Tihfor TS t Ti

Wmin (Ti ) t 0
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) in harbor condition should also be checked by
the following formulae in addition to the requirements in [2.2.2]:

January 2006

Page 59

Chapter 4, Appendix 1

Common Structural Rules for Bulk Carriers
for TS t Ti t 0.67TS

Wmax (Ti )M FullWmax (Ti )M Full  1.025VH

0.67TS  Ti
hfor Ti  0.67TS

Examples for mass curve of cargo hold for BC-B or BC-C ships are shown in Fig 3.

(a) Without {No MP}
Figure 3:(b) With {No MP}
Example of mass curve for BC-B or BC-C ships

2.2 Maximum permissible mass and minimum required masses of single cargohold in harbour condition
2.2.1 General
The cargo mass curves of single cargo hold in harbour condition are defined in [2.2.2]. However if the ship structureis checked for more severe loading conditions than ones considered in Ch 4, Sec 7, [3.7.1], the minimum requiredcargo mass can be based on those corresponding loading conditions.

2.2.2 All ships
The maximum permissible cargo mass and the minimum required cargo mass corresponding to draught for
loading/unloading conditions in harbour may be increased or decreased by 15% of the maximum permissible mass at
the maximum draught for the cargo hold in seagoing condition. However, maximum permissible mass is in no caseto be greater than the maximum permissible cargo mass at designed maximum load draught for each cargo hold.

3. Maximum and minimum masses of cargo of two adjacent holds
3.1 Maximum permissible mass and minimum required masses of two adjacent
holds in seagoing condition
3.1.1 General
The cargo mass curves of two adjacent cargo holds in seagoing condition are defined in [3.1.2] and [3.1.3]. However
if the ship structure is checked for more severe loading conditions than ones considered in Ch 4, Sec 7, [3.7.1], theminimum required cargo mass and the maximum allowable cargo mass can be based on those corresponding loading
conditions.

Page 60

January 2006

Common Structural Rules for Bulk Carriers

Chapter 4, Appendix 1

3.1.2 BC-A ships with “Block loading”
The maximum permissible cargo mass ( Wmax (Ti ) ) and the minimum required cargo mass ( Wmin (Ti ) ) for theadjacent two holds at various draughts ( Ti ) are determined, in t, by the following formulae:
without {No MP},The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the greater of the following
formulae:¦ (MWmax (Ti )blk 0.1M H )  1.025(V f  Va )Full

 1.025(V f  Va )TS  Tihor¦M

Wmax (Ti )(0.67Ts  Ti )hHowever, Wmax (Ti ) is no case to be greater than Mblk.
The minimum required mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the lesser of the following
formulae:

Wmin (Ti )0Wmin (Ti ) 1.025 V f  Va

Ti  0.75TShforTi  0.75TS

for

TS t Ti ! 0.75TS

with {No MP},The maximum permissible mass (¦ (MWmax (Ti )blkWmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formula: 0.1M H )  1.025(V f  Va )TS  TihHowever, Wmax (Ti ) is no case to be greater than Mblk.
The minimum required mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the lesser of the following
formulae:
Wmin (Ti )for Ti d T HB

0Wmin (Ti ) 1.025 V f  Va

Ti  THBhfor TS t Ti ! T HB
The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) in harbor condition should also be checked by
the following formulae in addition to the requirements in [3.2.2]:

Wmax (Ti )

¦M

Full

 1.025(V f  Va )(0.67Ts  Ti )hWmax (Ti ) d ¦ M blk
Examples for mass curve of cargo hold for BC-A, block loading ships are shown in Fig 4.

January 2006

Page 61

Chapter 4, Appendix 1

Common Structural Rules for Bulk Carriers(a) Without {No MP}
Figure 4:(b) With {No MP}

Example of mass curve for BC-A ships, block loading

3.1.3 BC-A ships without “Block loading” and BC-B, BC-C ships
The maximum permissible cargo mass ( Wmax (Ti ) ) and the minimum required cargo mass ( Wmin (Ti ) ) for theadjacent two holds at various draughts ( Ti ) are determined, in t, by the following formulae:
without {No MP},The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formulae:

Wmax (Ti )

¦M

Full

Wmax (Ti )

¦M

Full

for TS t Ti t 0.67TS

 1.025 V f  Va

0.67TS  Ti
hfor Ti  0.67TS

The minimum required mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the lesser of the following
formulae:

Wmin (Ti )0forWmin (Ti ) 1.025 V f  Va

Ti  0.75TShTi  0.75TS

for TS t Ti ! 0.75TS

with {No MP},The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the following formula:¦M

Wmax (Ti )Full 1.025 V f  Va

TS  Tihfor Ti  TSThe minimum required mass ( Wmin (Ti ) ) at various draughts ( Ti ) is obtained, in t, by the lesser of the following
formulae:
Wmin (Ti )Wmin (Ti ) 1.025 V f  Va

Page 62

for Ti d T HB

0

Ti  THBhfor TS t Ti ! T HB

January 2006

Common Structural Rules for Bulk Carriers

Chapter 4, Appendix 1

The maximum permissible mass ( Wmax (Ti ) ) at various draughts ( Ti ) in harbor condition should also be checked by
the following formulae in addition to the requirements in [3.2.2]:

Wmax (Ti )

¦M

Full

Wmax (Ti )

¦M

Full

 1.025(V f  Va )0.67TS  Tihfor

TS ! Ti ! 0.67TS

forTi  0.67TS

Examples for mass curve of cargo hold for BC-A, NO block loading ships and BC-B, BC-C are shown in Fig 5.

(a) Without {No MP}
Figure 5:(b) With {No MP}

Example of mass curve for BC-A ships, NO block loading and for BC-B and BC-C ships

3.2 Maximum permissible mass and minimum required masses of two adjacentcargo holds in harbour condition
3.2.1 General
The cargo mass curves of two adjacent cargo holds in harbour condition are defined in [3.2.2]. However if the ship
structure is checked for more severe loading conditions than ones considered in Ch 4, Sec 7, [3.7.1], the minimum
required cargo mass can be based on those corresponding loading conditions.
3.2.2 All ships
The maximum permissible cargo mass and minimum required cargo mass corresponding to draught for
loading/unloading conditions in harbour may be increased or decreased by 15% of the maximum permissible mass at
the maximum draught for the cargo hold in seagoing condition. However, maximum permissible mass is in no caseto be greater than the maximum permissible cargo mass at designed maximum load draught for each cargo hold.

January 2006

Page 63

KC#673
Regarding the determination of the still water bending moments according to Ch.4, Sec.3,
2.2.2, excerpted below:

The wave bending moments are given in 3.1.1, excerpted below:

When determining the still water bending moments for fatigue, fp, used in 3.1.1 should betaken as 1.0, rather than 0.5 which is normally used for fatigue related calcs. The reason isthat the Rule estimated design still water bending moments should be independent of theprobability of occurrence, which is what the fp factor is.

KC#694

Load calculation pointDKC#851 Question
CASE (A)

BH/2
\

h2
J

/2

Lower stool top

h3

bIB

CASE (B)

BH/2
\

h2
J

Lower stool top
/2

h3

bIB

KC#851 Answer

Common Structural Rules for Bulk
Carriers
Proposals for the calculation of the dry bulk cargo's upper surface height

20 May 2009Common Structural Rules for Bulk Carriers

20/05/2009

Revision history

i

Date

AuthorSociety

Description

20 Mai 2009

EtienneTiphineBureau Veritas

Revision .

Proposals for the calculation of the dry bulk cargo's upper surface height20/05/2009

Common Structural Rules for Bulk Carriers

Table of contents
Overview of the problem ............................................................................................................................................. 1
DNV approach .............................................................................................................................................................. 1
BV proposals ................................................................................................................................................................ 1
First approach .......................................................................................................................................................... 1
Second approach...................................................................................................................................................... 2
Sloped upper surface ................................................................................................................................................... 2
Numerical comparisons ............................................................................................................................................... 3
Conclusion .................................................................................................................................................................... 4

Proposals for the calculation of the dry bulk cargo's upper surface height2

Common Structural Rules for Bulk Carriers

20/05/2009

Overview of the problem
There is a possibility that, for certain combinations of hold geometries and cargo densities, the lower limit of the
cargo͛s upper surface falls below the upper knuckle of the lower stool.
Unfortunately, this is not explicitly considered in the CSR BC documents.
DNV was the first to propose an approach. On this basis, this document provides another formulation, a variation
on it and lastly a comparison of the results given by the current formulas in CSR BC and these 3 proposals.

DNV approachth/Ŷ ĚŽĐƵŵĞŶƚ ͞ĂůĐƵůĂƚŝŽŶ ŽĨ >ŽĂĚ ŚĞŝŐŚƚ ʹ DNV proposal ʹ SESOL ʹ 10 DĂƌĐŚ ϮϬϬϵ͕͟ ƚŚĞ Es establishes thefollowing formula:with the following assumptions:xx

h3 only to be calculated when h1 is less than 0
Volume of transverse stools is assumed to be
fully considered regardless of shape and heightof cargo (Conservative)dŚĞďƌĞĂĚƚŚ͛ŝƐƚŚĞŶŐŝǀĞŶďǇ͗

BH.DNV § 4 tan ( J )  U  b 2 l  U  b 2 l  tan § \ ·  16 U  V  16 M·¨¨ ¸¸
C IB H
C H H
C TS
©
© 2¹
¹
\·
§
2 UC lH tan ( J )  tan ¨ ¸© 2¹Figure 1: DNV proposal.

BV proposals
First approach
As DNV, it is considered ƚŚĂƚƚŚĞďƌĞĂĚƚŚŽĨƚŚĞŚŽƌŝǌŽŶƚĂůƉĂƌƚŽĨƚŚĞĐĂƌŐŽ͛ƐƵƉƉĞƌƐƵƌĨĂĐĞŝƐď H / 2 and that thevolume of the lower transverse stool is fully considered in the calculations.

2§M

bH / 2b1 

bH / 4

h21

hC1
h11

lH ¨ UC©

 VTS·¸ ¹2b IB  h HPL
b H  b IB

h HPL
b H  b IB

12

 tan §¨\2
 b  tan §¨ ·¸
8 H
© 2¹
1

\·

¸
© 2¹

\/2

S21
b1





S11

hHPL

bIB / 2

Figure 2: BV first approach.

1

Proposals for the calculation of the dry bulk cargo's upper surface height0.5

20/05/2009

Common Structural Rules for Bulk Carriers

After some geometric calculations, the breadth b1 isgiven by:
In turn, the other values are defined as follow:

h 11  h HPL

h21 

b 1  b IB
b H  b IB

bH ·
1§
\
 ¨ b1 ¸  tan §¨ ¸·
2©
2 ¹
© 2¹

And

hc1  h11  h21

Second approach
Here ƚŚĞ ĂƐƐƵŵƉƚŝŽŶ ŝƐ ŵĂĚĞ ƚŚĂƚ ƚŚĞ ďƌĞĂĚƚŚ ŽĨ ƚŚĞ ŚŽƌŝǌŽŶƚĂů ƉĂƌƚ ŽĨ ƚŚĞ ĐĂƌŐŽ͛Ɛ ƵƉƉĞƌ ƐƵƌĨĂĐĞ ŝƐ half of theďƌĞĂĚƚŚŽĨƚŚĞĐĂƌŐŽ͛ƐƵƉƉĞƌƐƵƌĨĂĐĞĂƚŝƚƐůŽǁĞƌĐŽƌŶĞƌ, i.e. b2 / 2.
Similarly to DNV, the volume of the lower transverse stool is fully considered in the calculations.
After some other geometric calculations, thebreadth b1 is given by:

bH / 2b2 b2 / 4

h22

hC2

\/2

S22
b2

h12

In turn, the other values are defined as follow:
hHPL

S12

2

1 h HPL b IB
 VTS·¸ ¨lH UC©
¹ 2 b H  bIB\ ·1 § h HPL3
 tan §¨ ·¸ ¸¨
2 b H  b IB
8
© 2 ¹¹©
1§M

bIB / 2b 2  b IB
h 12  h HPLb H  b IB

h22 

Figure 3: BV second approach.

\b  tan §¨ ¸·
4 2
© 2¹
1

And

hc2  h12  h22

Sloped upper surface
The sloped part of the cargo͛s upper surface is given by the following formulas, provided all the heights given
herein have been calculated:
CSR

DNV / BV first approach

BV second approachh23
zCSR ( y)  hDB  hHPL  h13  22y  bH
bH
2h21
zBV1 (y)  hDB  h11 
2y  b1bH  2b1
h22
zBV2 ( y)  hDB  h12  2
2y  b2
b2

Proposals for the calculation of the dry bulk cargo's upper surface height2

Common Structural Rules for Bulk Carriers

20/05/2009

Numerical comparisons
On the basis of the example provided by DNV in its document:
Hold geometry

Cargo description

Length of the holdlH

28.80 mBreadth of the holdbH

32.26 mBreadth of the inner bottombIB

22.40 mHeight of the hopper above the inner bottom

hHPL

3.40 mVolume of the transverse stool

VTS

187.40 m3

Total mass in the cargo holdW

8000.00 t

Density of the cargoU3.00 t/m3

Angle of repose of the cargo\

35.00 °

The following sets of values have been calculated:
Description

Variable

CSR BC

BV 1

BV2

DNV

Breadth of the cargo upper surface atthe point of contact with the hopper͛͖ď1 ; b2

32.6000 m

28.6428 m

28.3136 m

28.6431 m

h03.4000 m

h1-1.7157 m

2.1527 m

2.0392 m

2.1526 m

h2

2.5429 m

1.9726 m

2.2318 m

1.9727 m

hC

4.2272 m

4.1253 m

4.2710 m

4.1253 m

Height of the upper surface at bH / 4z(bH / 4)4.2272 m

4.1253 m

3.9599 m

4.1253 m

Variations of hC/CSR-2.41 %

+1.04 %

-2.41 %Height of the horizontal part of the
cargo upper surface/BV1+3.53 %

/BV2
Variation of ͛͖ď1 ; b2

/CSR

-12.14 %/BV1-13.15 %-12.14 %-1.15 %

0.00 %/BV2
Variation of z(bH / 4)

/CSR

0.00 %-3.53 %

+1.15 %
-2.41 %

/BV1

-6.32 %

-2.41 %

-4.01 %

0.00 %

Verifications have been made by calculating the corresponding mass of cargo on the basis of the volume used by
the cargo and its density. In each case, the initial value of 8000 t is obtained.
The following figure gives the different shapes of the cargo͛s upper surfaces.

3

Proposals for the calculation of the dry bulk cargo's upper surface height20/05/2009

Common Structural Rules for Bulk Carriers

10

8

¢ 1²
hold
¢ 1²
CSR
¢ 1²
BV1

6

¢ 1²
BV2
¢ 1²
h.CSR
h.BV1¢ 1²

4

¢ 1²
h.BV2

2

1.9
0

0

5

10

15

Figure 4: shapes of the cargo͛s upper surface.

Conclusion
The above values show that:xxx

DNV approach and BV first approach give the same results; the difference is only on the variables used in theformulas.
The volume of the cargo is correctly given by the CSR formulation even for this kind of configuration.
Regarding the differences between these 4 approaches:x

All the horizontal parts of the cargo͛ƐƵƉƉĞƌƐƵƌĨaces are close from each others.
Considering all the approximations already made for modelling the shape of the cargo, these differences
are not significant;x

The sloped parts of the cargo͛ƐƵƉƉĞƌƐƵƌĨĂĐĞƐŚĂǀĞƚŚĞƐĂŵĞŝŶĐůŝŶĂƚion.
Hence, the only largest difference is between the current CSR approach and the second proposal madeby BV, due to the difference in breadth of the horizontal part of the cargo͛ƐƵƉƉĞƌƐƵƌĨĂĐĞ͘
However, these differences remain small and can be neglected;x

The breadth of the hold submitted to the cargo load is significantly reduced in each of the 3 new
propositions.
As the loads (dry bulk cargo pressurĞ͕ŝŶĞƌƚŝĂůƉƌĞƐƐƵƌĞ͕ƐŚĞĂƌůŽĂĚ͙ͿĂƌĞůŝŶĞĂƌĨƵŶĐƚŝŽŶƐŽĨƚŚĞĐĂƌŐŽŚĞŝŐŚƚ͕ƚŚĞ
consequences of these differences are also limited.
The first intent of this proposal (DNV, BV1 and BV2 approaches) is to have a better description of the space usedby the cargo in the hold.
The first drawback of these alternative proposals is the reduction of the breadth of the hold submitted to thecargo load compared to the current CSR BC approach.
The second drawback is the increase in the complexity of the rules for that part as it is needed to make thedifference between the cases where the hold is filled above the hopper and those where the hopper is not fully
covered by the cargo.
As the difference in the cargo height are not significant but as the impacted breadth of the hold is lesser with the
new approach, it is more conservative and simpler to keep the CSR BC as they are.
However, it could be of interest to benefit of the forthcoming harmonisation for improving the bulk load approach.

Proposals for the calculation of the dry bulk cargo's upper surface height4

KC#907
Dear Sir or Madam,
I have some questions about CSR for bulk carrier in Chapter 4 section 6 Internal Pressures and Forces
The dry bulk cargo pressure in still water Pcs is given by
pCS = ȡC gKC (hC + hDB í z)

Where
KC = cos2Į + (1í sinȥ )sin 2Į
Į : Angle, in deg, between panel considered and the horizontal planeȥ : Assumed angle of repose, in deg, of bulk cargo (considered drained and removed); in the absence ofmore precise evaluation, the following values may be taken:Question1
Forloadingconditionwherethecargoholdisnotloadedtotheupperdeck(Chapter4,Section6,
1.1.2)


Asshowninthefigureabove,
a.Whetherthecargopressuresinthestillwaterforinnerbottomregion1and2arethesameor
notsinceitseemsthatthecargoheightsaredifferentforthesetwoareas?Ifnot,thecargopressureforinnerbottom2shouldbepCS = ȡC gKC (ha + hDB í z) or not?
b.WhetherthePcsforthesidearea4iszeroalthoughthisareaisbelowhc?
c.Whencalculatingthestillcargopressuresonthehoppertankplate,shouldIusepCS = ȡC gKC (hc + hDB í z) or pCS = ȡC gKC (hb + hDB í z)d.For the cargo pressures on the side, should I use hd instead of hc?
Question2Forloadingconditionwherethecargoholdisloadedtotheupperdeck(Chapter4,Section6,1.1.1)


a.Inthiscase,whatisthevalueofȥ? 0°ortheangelbetweentopsidetankplateandthehorizontal
plane?
b.Whetherthecargopressuresinthestillwaterfortheinnerbottomregion1and2arethesameor
not?
c.Forthehoppertankplate,shouldIusehbinsteadofhc?


KC#987

KC#1023

One:

Two:

Three:

KC#1025

KC#1054
Regarding the hc value of the dry bulk cargo in full-filled condition in which the cargo holdis loaded up to the top of hatch coaming, Ch4/Sec6/1.1.1 of CSR-BC specifies theprocedure of calculating the height of dry cargo upper surface(Method 1). Meanwhile aformula for calculating the hc value is given specifically for holds of cylindrical shape(Method 2).
For a typical bulk carrier, upper stools are generally arranged in the cargo hold. The hc
values will be different by using the above two procedures. A detailed comparison
between the two methods is given as below.

1.

Method 1: Calculation of hc using “real volumes”

hc = hHPU + Vupper part / Alower part
Vupper part = VMFULL – Vlower part
VMFULL: Volume of the cargo hold including the volume enclosed by the hatch coaming.
Vlower part: Volume of the cargo hold filled up to the lower intersection of the top side tankand shell or inner side.
Alower part: Area of the upper surface of Vlower part(red area in Fig. 2).
Vupper part: Volume of the cargo hold part above the lower intersection of the top side tankand shell or inner side, excluding the volume of upper stool.
hHPU: Vertical distance between inner bottom and lower intersection of top side tank andshell or inner side.

Fig1: VMFULL

2.

Method 2: Calculation of hc using “formula”

Fig2: Alower part

hc = hHPU + h0
where:

hHPU: Vertical distance, in m, between inner bottom and lower intersection of top side tankand side shell or inner side, as the case may be, as defined in Fig 3.
S0: Shaded area, in m2, above the lower intersection of top side tank and side shell or
inner side, as thecase may be, and up to the upper deck level, as defined in Fig 3.
VHC: Volume, in m3, enclosed by the hatch coaming.

" H : Length, in m, of the compartment.
BH: Mean breadth of the cargo hold, in m.

Single side bulk carrier

Double side bulk carrier
Fig3: Definitions of hc, h0, hHPU and S0

3.

Pressure comparison of the two different methods for hc calculation:

Loading condition:

Fig4: Full-filled loading condition

Elements for pressure comparison:

Fig5: Elements for Inner Bottom Plate

Fig6: Elements for Bilge Hopper Plate
Pressure comparison of the two different methods:
Pressure(N/mm2)
Structural
MemberPoint ID

1
Inner Bottom
Plate

2
3

Bilge Hopper
Plate
4.

1

Method1(hc=16.024
m)

Method2(hc=16.212
m)

P

0.21710.2196

S

0.21280.2154P

0.21900.2215

S

0.21100.2135

P

0.22140.2239S

0.20860.2111P

0.15900.1609S

0.14410.1460Port/Starboard

Cause of the difference

In method 1, the volume of upper stool within cargo hold is deducted from the volume ofupper part. The volume is real cargo volume.
In method 2, the volume of upper stool within cargo hold is included in the volume of upper
part. Obviously, the volume is approximate to the real cargo volume.
There is no difference between the two methods for the cylindrical shape hold without
Upper Stool.