bulk carrier presentation

1

BULK CARRIER

Hull Structural approach

2

SUMMARY

1.Introduction

2. Damage to Bulk Carrier

3. Bulk Carriers hull design

with IACS UR

4. BV approach

3

Introduction

4Bureau Veritas

Introduction

CapesizeBulk Carrier+80,000dwt527 ships of

82.5 million dwt

PanamaxBulk Carrier60-80,000dwt888 ships of

61.5 million dwt

HandymaxBulk Carrier40-60,000dwt976 ships of

44.9 million dwt

HandysizeBulk Carrier10-35,000dwt2,945 ships of

78.7 million dwt

Iron oreCoal

Grain Salt

Iron oreCoalGrain

BauxitePhosphate

Graincoal

Steel prod.CementPotash

RiceSugar

GypsumForest prod.

ScrapSulphur

Combined Carriers151 Ships of15.1 M. dwt

► The Bulk Carrier Market

5Bureau Veritas

Introduction

HEAVY BULK

MULTIPURPOSE

LIGHT BULK

► Type of Loading

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Introduction

► Single side bulk carrier

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Introduction

► Double side bulk carrier

8

Damage to Bulk Carriers

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► Trends of Losses at Sea

0

0.5

1

1.5

2

2.5

dwt

1970 1974 1978 1982 1986 1990 1994 1998

Combos

Bulkers

Tankers

10Bureau Veritas


► Bulk carrier losses

A crew safety problem

LOSS OF LIVES

0

20

40

60

80

100

120

140

160

180

200

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

Years

No

. li

ves

lost

BULK CARRIERS LOST

0

5

10

15

20

25

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

Years

No

. ve

sse

ls l

ost

Source: Intercargo

11Bureau Veritas

Primary causes of casualties

Considering data from 1999 to 2000, primary causes of fatalities are:

1. Hull damages2. Navigation error3. Fire and explosion4. Machinery failures

Oil tankers

0%

5%

10%

15%

20%

25%

30%

35%

Bulk carriers

Ma

chin

ery

fa

ilure

na

vig

atio

n e

rro

r

fire

an

d e

xplo

sio

n

hu

ll fa

ilure

mis

cella

neo

us

0%

10%

20%

30%

40%

50%

60%

70%

80%

Machinery failure

navigation error

fire and explosion

hull failure

miscellaneous


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0.00E+00

5.00E-04

1.00E-03

1.50E-03

2.00E-03

2.50E-03

3.00E-03

Hatchcover Pipes&valves

Side Shell Side Shell(Collision)

Bottom Shell Deck Side ShellPenetration

categories of incidents

fre

qu

en

cy

of

inc

ide

nts

pe

r s

hip

y

ea

r

Mini

Handysize

Handymax

Panamax

Cape size


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► Type of Damages

• cracking at hatch corners;

• plate panel buckling of cross deck strips and stiffening structure;

• cracking of hatch coamings;

• cracking at the intersection of the inner bottom plating and the hopper/stool platings

• grab and bulldozer damage to the main frames lower brackets

14Bureau Veritas


► Type of Damages

• cracking at main frame bracket toes

• corrosion within topside tanks, of the tranverse bulkheads, the frames and brackets

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► Type of Damages

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► Type of Damages

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► Type of Damages – Hatch Covers

• 1 or 2 case of missing/lost hatch cover per year (excluding ships which sunk)

• N°1 hatch cover ten times more likely to be damaged than hatches from amidships to aft

18Bureau Veritas


► Rules into force - Conclusion

• IMO (SOLAS Ch. XII) : Safety

• IACS Requirements : strength of hull and stability

regulation URS 12,17,18,20,21,25,27…

• BV Rules April 2005 or CSR rules

includes IACS and IMO requiremetns

19

Bulk Carriers Hull designIACS UR requirements

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Bulk Carriers Hull design with IACS UR requirement

► IACS Rules for New Bulk

UR S12

- Requirements forSIDE STRUCTURES in single side skin (following UR Z11) Bulk Carrier

UR S17

- LONGITUDINAL STRENGTH of Hull girder in flooded condition

0,125 h

0,125 h

h

UR S18

- Scantlings requirements for Transverse corrugated watertight bulkheads in flooded condition for each hold (only single side skin B/C following URZ11)

UR S1/1 A

- Requirements for loading conditions, loading manuals, loading instruments and loading sequences

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UR S20

- Scantlings requirements for Double Bottom in flooded condition for each hold (only single side skin B/C following URZ11)

Ex UR S24 replaced by SOLAS Ch. XII Reg. 12 and 13 (Resolution MSC 134 (76) and MSC 145 (77)) + UI SC 179/180

-Cargo hold, ballast and dry space water level detectors (REG. 12) – (regardless date of construction)-Dewatering of forward spaces of B/C (REG. 13) – (regardless date of construction)

UR S21

- Strength requirements for Hatch Covers and coamings located forward of 0.25 L from the fore perpendicular

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UR S25

- harmonized notations and corresponding design loading conditions including Mass Curves definition

UR S27

- Strength requirements for fore deck fittings (Ventilator and air pipes) and equipments (Windlasses)

UR S26

- Strength and securing of SMALL HATCHES on the exposed fore deck

UR S28

- Requirements for the fitting of a FORECASTLE

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► UR S1 and UR S1A : Loading Instrument and Manual

• Loading Instrument

• all existing bulk carriers of both single and double side skin construction

• Loading Manual

• all existing single side skin bulk carriers

• all new bulk carriers, ore carriers and combination carriers

• includes Loading sequences for single side skin bulk carriers >= 150m built before 1/7/98

• includes Loading sequences for all new bulk carriers >= 150m built after 1/7/98

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► UR S12 : Side Structures

• Minimum thickness of frame web :

t w,min = C(7 + 0.03 L) (+ 15% in foremost hold)

• Minimum thickness of side shell :

• Requirements for construction of upper and lower brackets

• Welding requirements

• No combined load « cargo + sea water » considered

0,125 h

0,125 h

h

0,125 h

0,125 h

h

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► UR S17 : Longitudinal Strength of Hull Girder in Flooded Condition

• Flooding of any hold in any loading condition :

• equilibrium calculation: MSW and FSW in flooded condition

• calculation of under MSW + 0.8 MW

under FSW + 0.8 FW

Typical reinforcements induced by UR S17 > adm increase of section modulus in midship area

(increase of deck thickness)

> adm increase of side shell thickness in way of

transverse bulkhead

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► UR S18 : Corrugated transverse watertight bulkhead

• Calculation of pressure induced by flooding

(design load= cargo + sea water):

bending moment and shear force acting on the bulkhead

• Checking of section modulus of the corrugation under the bending moment (taking into account

gussets or shedder plates)

Gusset PlatesGusset Plates

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► UR S18 : Corrugated transverse watertight bulkhead

• Checking of shear stress in web of the corrugation with requirement for shear buckling

• Strength of plate under local pressure

• Requirements for construction of upper and lower stools and alignment conditions

► Typical reinforcements induced by UR S18

• Increase thickness of flange / web of corrugation

• Gusset or shedder plates

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► UR S20 : Allowable hold loading

• Calculation of shear strength of the double bottom to obtain the allowable hold loading considering hold flooding

• Sum of shear areas of floors and girders taking into account holes if any

► Typical reinforcements induced by UR S20

• Increase thickness of flange / girders at their ends

• Add partial floors / girders

• Remove holes

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► UR S21 : Hatch Cover• Design load based on green sea on deck

• Only hatch covers located forward of 0.25 L from the fore perpendicular

• Direct calculation of primary members (with effective width for compression flanges) under pressure

• Allowable stresses: a = 0.8 F (yieldstress)

a = 0.45 F

2 5 . 72 5 . 7

pp ( P a )( P a )5 6 . 55 6 . 5

8 2 . 28 2 . 2

0 . 2 5 L 0 . 1 L F P

2 5 72 5 7

8 8 . 68 8 . 6

5 8 . 85 8 . 8

P ( P a )P ( P a )

2 5 . 72 5 . 7

pp ( P a )( P a )5 6 . 55 6 . 5

8 2 . 28 2 . 2

2 5 . 72 5 . 7

pp ( P a )( P a )5 6 . 55 6 . 5

8 2 . 28 2 . 2

2 5 . 72 5 . 7

pp ( P a )( P a )5 6 . 55 6 . 5

8 2 . 28 2 . 2

0 . 2 5 L 0 . 1 L F P

2 5 72 5 7

8 8 . 68 8 . 6

5 8 . 85 8 . 8

P ( P a )P ( P a )

0 . 2 5 L 0 . 1 L F P0 . 2 5 L 0 . 1 L F P

2 5 72 5 7

8 8 . 68 8 . 6

5 8 . 85 8 . 8

P ( P a )P ( P a )

2 5 72 5 7

8 8 . 68 8 . 6

5 8 . 85 8 . 8

P ( P a )P ( P a )

2 5 72 5 7

8 8 . 68 8 . 6

5 8 . 85 8 . 8

P ( P a )P ( P a )

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► UR S25 : Harmonized notations and corresponding design Loading conditions for B/C

• Definition of notation

• BC-A dens>1t/m3, + specified empty hold at maximum draught, + BC-B conditions.

• BC-B dens>1t/m3, + no empty hold, + BC-C conditions.

• BC-C dens<1t/m3

• Definition of design loading conditions for checking of rules criteria regarding longitudinal strength

• Definition of design loading conditions for checking of rules criteria regarding local strength (primary and secondary members)

• Definition of the hold mass curves to be included inside Loading Manuel and Instrument.

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BV approach

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BV approach

► Critical Point

Members Connection with

Inner bottom plating Sloping and /or vertical plate of lower stool

Sloping plate of hopper tank

Inner side plating Sloping plate of hopper tank

Transverse bulkhead Sloping plate of lower stool

Sloping plate of upper stool

Frames of single side bulk carriers

Upper and lower wing tank

Ordinary stiffeners in double bottom

Floors in way of transverse bulkheads

Hatch corners Free edges of hatch corners

Hatch coaming ends Upper deck

Hatch cover stopper Fx, Fy, Fz Stopper

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BV approach

► Critical Point

Double bottom in way of transverse bulkheads

CONSTRUCTION NDE :

• Misalignment (median lines) between floor and bulkhead (or stool) plating t /3.

• Cut-outs for connections of the inner bottom longitudinals to double bottom floors to be closed by collar plates welded to the inner bottom.

The following NDE are required :

• VE 100%,

• UE 35% of full penetration weld for absence of cracks, lack of penetration and lamellar tears

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BV approach

► Critical Point

Double bottom in way of hopper tanks

CONSTRUCTION NDE :

• Misalignment (median lines) between girder and sloping plate tA /3.

• Misalignment (median lines) between floor and hopper transverse web tB/3.


• VE 100%,


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BV approach

► Critical Point

Lower part of inner side (In case of double hull)

CONSTRUCTION NDE :

• Misalignment (median lines) between hopper tank top plate and hopper tank sloping plate tA /3.

•. Misalignment (median lines) between members above and below hopper tank top plate tB /3.

• If not full penetration welding of hopper tank top plate to inner side, the weld preparation is to be indicated on the approved drawings.

• Butt welds between inner side and hopper tank sloping plate at a distance greater than 500mm from the hopper tank top plate.


• VE 100%,


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BV approach

► Critical Point

Lower part of transverse bulkheads with lower stools

CONSTRUCTION NDE :

• Misalignment (median lines) between corrugation flanges and stool side plating tA /3.

•. Misalignment (median lines) between lower edge of shedder plates and stool side plating tB /3.

• Knuckled shedder plates are to be avoided.

•Corrugation radius according to Ch 4, Sec 7, [3.1.3].


• VE 100%,

• UE 35% of full penetration weld for absence of cracks, lack of penetration and lamellar tears.

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BV approach

► Critical Point

Transverse corrugated BHD with upper stool or top side tank

CONSTRUCTION NDE :

Misalignments between :

• Transverse web or intercostal reinforcement fitted inside the upper wing tank and corrugation flanges,

• Transverse web or intercostal reinforcement fitted inside the upper wing tank and upper stool side plating,

• Upper stool side plating and corrugation flanges, are to be t /3.


• VE 100%, with particular care for fillet shape and undercuts on the plating,


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BV approach

► Critical Point

Side frames with hopper and topside tank

CONSTRUCTION NDE :

• Misalignment (median lines) between flame web and the connecting brackets inside hopper tank and upper wing tank t /3, where t is the minimum thickness among those of the connected elements.

• Soft toe : tapering of frame flange at ends : thickness 1:3, width 1:5.


• VE 100%, with particular care for fillet shape and undercuts on the plating at the soft toes,

• ME or dye penetrant depending on the results of VE.

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BV approach

► Critical Point

Double bottom longl. In way of transverse BHD stool

CONSTRUCTION NDE :

• Misalignment between webs of bottom and inner bottom longitudinal with floor stiffener t /3.

• In case of fillet weld, misalignment may be as necessary to allow the required fillet leg size, but 10mm.

Visual examination 100%.

40Bureau Veritas

BV approach

► Critical Point

Hatch corner

CONSTRUCTION NDE :

• Corners of insert plates to be rounded, unless corresponding to joints of deck strakes.

• Insert cut edges to be carefully executed.


• VE 100%,

• RE / UE in areas indicated in the sketch.

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BV approach

► Critical Point

Ends of longl. Hatch coamings

CONSTRUCTION NDE :

• Misalignment between bracket and under deck longitudinal tB /3.

• Soft tow : tapering of bracket flange at ends : thickness 1:3, width 1:5


• VE 100%, with particular care for the weld shape and undercuts on deck plating,

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Priorities for bulk carrier safety

• PRIORITY 1 strengthen the side shell to prevent flooding

• PRIORITY 2 avoid progressive flooding

• PRIORITY 3 alert the crew to the occurrence of flooding at the very first stage

BV approach

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►Rules entered into force after July 1st, 1998 : Existing & New Ships

BV approach

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We are ready to go!

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bulk carrier presentation

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