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Recent developments on Recent developments on cutter dredgerscutter dredgers

6th May 2008M.O. Boor IHC Merwede E.C. van der Blom IHC Merwede

Cutter dredgers for the Gulf area

2Contents

New dredgersFeaturesSimulation of spud carriage behaviour

3New dredgers

Complete range (being) built 2006 – 2010

Total power 4,080 kW, cutter motor 1100 kWto

Total power 15,700 kW, cutter motor 3000 kW

44,080 kW CSD (Albzem)

Length over all, approx. 65.50 mLength over pontoon 51.10 mWidth 14.00 mDepth 4.20 mMax. draught, approx. 3.15 mMaximum dredging depth 16 mDiameter suction pipe 700 mmDiameter discharge pipe 650 mmTotal installed power 4080 kWCutter power 1100 kWPower dredge pump drive 1825 kWMain generator sets (2x) 1025 kWAuxiliary generator set 205 kW

516,500 kW CSD (Huta 10)

Length over all, approx. 124.50 mLength over pontoon 100.10 mWidth 20.30 mDepth 6.30 mAverage draught. 4.40 mMax. dredging depth 25 mDiameter suction pipe 900 mmDiameter discharge pipe 900 mmTotal installed power 15,700 kWCutter motor power 3000 kWPower submerged

dredge pump 1500 kWPower inboard pumps 2 x 3800 kWMain generator sets 2 x 3700 kW

64,960 kW CSD (Inai Delima)

Length over all, approx. 67.60 mLength over pontoon 51.80 mWidth 14.00 mDepth 3.40 mAverage draught 2.35 mMax. dredging depth 22 mDiameter suction pipe 750 mmDiameter discharge pipe 750 mmAccommodation 20 personsTotal installed power 4960 kWCutter power 750 kWSubmerged pump drive 1641 kWBooster pump drive 1641 kW

713,000 kW CSD

Length over all, approx. 100.00 mLength over pontoon 79.80 mWidth 18,40 mDepth 4.90 mAverage draught 3.50 mMax. dredging depth 29 mDiameter suction pipe 900 mmDiameter discharge pipe 900 mmAccommodation 26 personsTotal installed power 13,000 kWCutter power 1500 kWPower submerged

dredge pump drive 1500 kWPower inboard pumps 2 x 3700 kWMain generator sets 3 x 1717 kW

8Pumps

Cutter special pumps with large ball clearance (to match with 6 or 7 bladed cutters)High suction performance for shallow dredgingSame pump type submerged pump and inboard pump(s); single walled submerged, double walled inboardSame wear parts submerged pump and inboard pump(s) despite different execution (single/double walled)

9Drives

Identical motors for cutter and submerged pump where possible

10Other

High efficiency dredge pumps / pivoting gearboxPumps and engine room at deck levelSeparate accommodation on dampers

11Spud carriage

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Simulation of spud carriage behaviour

13Simulationmodel spud carriage

Targets:Knowledge of (flexible) spud carriage system behaviourPossibility to determine settings of spud carriage characteristicsDetermine safe settings for load limiters

Modelled systems:Spud carriageSpudWiresWire tensioning cylindersLoad limiter systemSpud carriage cylinder

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0 50 100 150 200 250 300 350 400-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

characteristic

spud carriageimposed translation

modelspud carriage

shipmodel

15CUDAS: CUtter Dredger At Sea

16Simulation with conventional spud

17Simulation with flexible spud

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3o

Fmax

δ

Fspud

Fsafe

spud protection

increasingly weak

increasingly stiff

linear weak

conventional

Buffering characteristics

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Wave period

Wav

e he

ight 89

simulations

HsTp / workability diagram

21Characteristics - spudforce

increasingly weak

spud protection

conventional

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topview

side view front view

cutterangle

Cutter movement in detail

side view

25Conclusions - flexibility

Flexibility in spud carriage:protects the spud against overloadimproves workabilitywill not have a negative effect on output

26Validation measurements

Ras Laffan, Qatar - december 2006

27Validation measurements

Ras Laffan, Qatar - december 2006Measurement of approx. 100 variablesMeasurement of wave climate with wave rider

28Validation measurements

Ras Laffan, Qatar - december 2006Measurement of approx. 100 variablesMeasurement of wave climate with wave riderMaximum wave conditons:- maximum height: 2,7 m- significant height: 1,6 m

Measured in several operational conditions

29Conclusions - simulation tool

Simulation tool provides:better understanding of internal forces, motions, system behaviour, etc.possibility to evaluate technical executions of flexible spud carriage systemspossibility to determine settings for flexible spud carriage systemsevaluation of workability of cutter dredgers

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Thank you for your attention