Wärtsilä virtual STW optimised by Eniram

Accurate STW data is a pre-requisite for any decisions related to evaluating vessel performance or speed related onboard operations. According to a study conducted by Eniram, among 300 vessels in 2017, a large portion of vessels (65% of cruise vessels) suffer significantly from speed log quality and performance evaluation accuracy is over or underestimated by more than 5%. This corresponds to speed logs being off by approximately 1,6%.

Rather than using just speed logs as a source of STW, Wärtsilä gathers information about the speed from multiple sources. Combining all of this data leads to an accurate indication of stw, enabled by Wärtsilä Virtual STW.

    Key features

    • Determining vessel fuel consumption more accurately
    • Evaluating performance through accurate speed power and fuel curves
    • Evaluating routes by accurate current calculations

    Case: Speed log quality assessment

    Case: Speed log quality assessment

    65% of cruise vessels suffer significantly from speed log quality, resulting in over/underestimation of performance accuracy by more than 5%


    Case: Measured and actual STW data

    Case: Measured and actual STW data

    A 3% off-set in speed logs, measured at 15 kn when actual speed is 15.4 kn, leads to an underestimation of vessel performance by 10% for average speed.


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