Sammendrag
The effect on the fuel consumption of external sailing conditions related to waves, wind, sea currents and hull fouling is substantial and generally should not be ignored. However, weather effects are usually dealt with in a simplistic manner (e.g. adding a weather margin) because of the complex and dynamic interaction between the various weather covariates. For instance, a vessel will be simultaneously subject to interacting waves, swells, wind and sea currents, potentially from different and varying directions and with different strengths over time. We propose a framework to reduce the dimensionality of the problem such that it is possible to assess and illustrate the impact of weather effects on the fuel consumption of a vessel (and its elasticity w.r.t both weather an speed). Our empirical data consist of vessel performance data for a large fleet of sister vessels in the Aframax and Suezmax crude oil tanker markets. Our results suggest that the true elasticity of a vessel’s fuel consumption, when subject to various severity of weather, is far from the theoretical flat water conditions and that the elasticity itself remains speed-dependent. We show that this means that the benefit from speed optimization (with regards to both profits and emissions) in the real seaway is substantially smaller than has hitherto been assumed in the literature. This has potentially profound effects on everything from maritime environmental policy and the financial benefit of weather routing.
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