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Avoiding Severe Weather While Eco-Steaming

December 17, 2017

Can a 7% savings from economical steaming increase voyage costs by 10%? Economical steaming is increasingly used by ships trading in a high fuel cost/low freight rate shipping market.

While there are benefits, operators must evaluate potential problems: the ramifications of speed instruction while considering weather conditions en route, and that fact that ships sailing at slower speeds will spend more time at sea and are more likely to encounter adverse weather.

In some cases, such as the example below, it may be prudent to consider alternate speed options during portions of a voyage to avoid weather situations that can lead to excessive steaming time and extra fuel consumption. In this case, a vessel sailed from Gulf of St. Lawrence to Norway during midwinter. The vessel was instructed to sail at an economical speed of 12.0kts to minimize fuel costs. Based on the estimated departure time, it became apparent that the vessel would likely encounter a large storm east of Newfoundland with BF 12 conditions and seas in excess of 10m.

  • Several route options were considered, including:
  • Increase ship speed at the onset to sail ahead of the developing storm, then resume economical speed once safe;
  • Maintain eco speed and adjust route as needed for best handling with gradual course adjustments returning to a direct route as conditions allowed; or
  • Commence drifting at a safe location outside of Cabot Strait to allow storm to pass ahead of the vessel, then resume direct voyage at an economical speed.

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 StormGeo designed an optimum passage based on different weather conditions that were predicted along the voyage, and speed and consumption rate options. The relevant voyage figures such as steaming time, estimated fuel consumption and average weather factors were then communicated to the voyage operator with additional analysis and suggestions. After discussion and review, the 3rd option to commence drifting was determined to be best choice for optimal vessel safety and fuel conservation.

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Had the vessel proceeded without StormGeo weather routing guidance, it is calculated that the excess steaming in heavy weather would have added 10% to the overall fuel costs. The eco-steaming terms on this voyage were designed to provide a 7% savings in overall voyage costs based on current rates. StormGeo services helped to ensure that the savings by eco-steaming are not subsequently lost by unnecessary exposure to heavy weather.

In these days of soaring bunker costs and depressed operating rates, simply invoking a slow steaming campaign for a fleet without taking into account the weather conditions can be potentially counter-productive and in some cases unsafe.