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VESTA-web（Ship Performance Simulator in Actual Seas）

VESTA-web is a program that simulates the ship speed and the fuel consumption under operational conditions.

Outline

VESTA-web is a program that simulates the ship speed and the fuel consumption under operational conditions. Regulations have been implemented by the International Maritime Organization (IMO) to reduce GHG (Greenhouse Gas) emissions from ships. The regulations using Energy Efficiency Design Index (EEDI) and Ship Operational Carbon Intensity Plan (SEEMP) began in 2013. Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII) based on fuel consumption performance of ships in service have begun in 2023.

By VESTA-web, the reduction of GHG emissions can be estimated and studied.VESTA-web also enables the estimation related to seakeeping performance (vertical acceleration, probability of slamming, probability for deck wetness, motion sickness incidence, etc.) and navigation performance of wind-assisted ships (sails and rotor sails).

Interface

In actual seas, the ships speed is reduced, and fuel consumption increases due to wind and waves. In such situation, VESTA-web enables the evaluation of the ship performance using fuel index which is introduced for energy saving operation.

Fuel index: Index of fuel input to the main engine

  • InputInterface

  • Output Interface

VESTA-web Calculation Details

(1) Estimation of external forces

  • ・Calculation of the added resistance, the lateral force, and the yaw moment*in waves and self-propulsion factors.
  • ・・・Calculations introducing tank test results with high accuracy (the tank test database is also available)
  • ・Calculation of added resistance due to wind・・・Regression formula based on wind tunnel test data

*Lateral force and yaw moment due to waves are calculated with zero velocity.

  • Example of output Frequency response of added resistance in regular waves (each wave direction)

  • Example of output
    Added resistance due to wind

(2) Performance simulator for a ship in actual seas

  • ・Calculation of fuel consumption
  • ・・・In addition to the torque limit of the main engine, governor operation modes (constant revolution, fuel index limits, constant power or constant speed) are considered.
  • ・Evaluation of seakeeping performance (vertical acceleration, probability of slamming, probability for deck wetness, motion sickness incidence, etc.)
  • ・Wind and waves (wind waves and swell) can be input and considered.
  • ・・・Directional spectrum, numerical prediction or measured on board can be input.
  • ・Evaluation of the performance of wind-assisted ships (sails and rotor sails)

  • Input screen

  • Example of power curve (relationship between ship speed and engine power) according to weather conditions

  • Example of fuel consumption output (FPD: fuel consumption per day [ton/day], FPM: fuel consumption per 1 nautical mile [ton/NM]) according to weather conditions

  • Estimation of probability of slamming (ppslam)

  • Estimation of percentage of vomiting (pv)

To use this application

Use of this app is limited to users in Japan.