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• Oil Sea Harvester Project
• OSH design
• Hydrodynamics and Optimisation

• Partners involved
• CAT Shipyard (FR) Design
• BEC hydrodynamic laboratory (FR) Numerical
  optimisation
• CEHIPAR hydrodynamic laboratory (SP) Test
  campaigns

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General Objective Optimisation of the
operational performances of the OSH concept

• Transit phase
• Powering performances relatively high transit
  speed
• Sea-keeping behaviour low dynamic responses
• Oil recovery Phase
• Sea-keeping behaviour for oil recovery operations
  up to sea state 6/7

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Transit phase powering optimisation

• Objective
• Light displacement (8000 t)
• Minimise the ship resistance at 25 knots
• Minimise all hydrodynamic interactionsat medium
  speeds
• Constraints
• Pods integration (immersion of the transom stern)
• central cylindrical part of the main hull not
  modified
• Lateral distance between the side hull and the
  main hull not modified (toll carriage and oil
  recovery tool integration)
• Design parameters
• Main hull
• Side hull

4
Powering optimisation Main hull modifications
Initial
Final

• Bow sections thinner waterline
• Buttock line and transom immersion
• Bulbous bow

Initial form
Initial
Final
Initial
Final
Optimal
5
Powering optimisation Side hull modifications

• Best length 101m (initial)
• Best longitudinal location fore

Best compromise between bow wave interactionsand
stern wave interactions
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Sea-keeping optimisation

• Objective sea-keeping performances
• Transit phase V 20 knots - ? 8 000 t Tool
  carriage in folded position
• Oil recovery operations V low speed ? 12
  000 t Tool carriage deployed
• Constraints
• Pods integration
• cylindrical part of the main hull not modified
• distance between the side hull and the main hull
• not modified (tool carriage integration)
• Design parameters
• Side hull
• Tool carriage

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Seakeeping optimisation for oil recovery
operations (Transit phase not critical)

• Increase of the side hull diameter 3.5m
  (instead of 3m)
• No influence of the longitudinal position of the
  side hulls
• Optimal length of the tool carriage 11.5m
• Optimal location of the tool carriage middle of
  the side hull

Example of results Influence of the length of
the tool carriage on the oil recovery
performances Operability diagram for 4 lengths
operability index (0-100) versus wave heading
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Optimal design

• Thinner bow sections
• Maximum transom immersion
• (Bulbous bow)
• Side hulls of length 101m at extreme fore
  location
• Tool carriage of length 11.5m located in the
  middle of the side hull

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Tank tests in progress (task 5.3) - assessment
of the design optimised numerically -
calibration of the numerical tools (re-used for
the final design stage)

• Resistance tests almost completed
• Great importance of the static trim
• (transom immersion)
• Optimal location of the side hull fore

Influence of the static trim

• Seakeeping tests carried out from June to
  September 06

Influence of the longitudinal Side hull location
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Thank you for your attention
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Seakeeping optimisation

• Definition of the operability value
• Transit phase
• Roll lt 12
• Pitch lt 4.5
• Vertical acceleration lt 3m/s²
• Oil recovery operations
• Wave elevation lt 1m
• Relative heave lt 3m
• Vertical acceleration lt 3m/s²
• Maximum significant height
• Operability diagramm

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Seakeeping optimisation Transit phase

• Better performances than in oil recovery
  operations
• No need to optimise

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Seakeeping optimisation Oil recovery operations

• Increase of the side hull diameter 3.5m
• No influence of the longitudinal position of the
  side hulls
• Optimal length of the tool carriage 11.5m
• Optimal location of the tool carriage middle if
  the side hull

Lngitudinal location of the side hulls
Length of the tool carriage