Ocean Currents
by Jim Sigafoose
The application of ocean currents in assessing vessel performance is an issue that has received inconsistent treatment in past London arbitration cases. There have been widely varying comments such as the following:
The tribunal did not accept that for currents to be taken into consideration, clear terms had to be expressed in the charter party. Ocean currents were a fact of life and should be taken into account in the normal course of events. Where currents were adverse, a vessel's performance should be credited. Where, as in the present case, the current was positive, the vessel's speed should be debited so as to arrive at an accurate assessment of her performance. (LMLN 670)
It is now common to see the term “no adverse current” mentioned in a charter party speed and consumption warranty; a recent arbitration (LMLN 720) held that in that case only the adverse current could be taken into account when considering whether the speed warranty was met. But without mention of favorable currents in the warranty, this would appear to still leave open to debate the application of these.
This topic was discussed by a panel of distinguished London arbitrators and maritime legal experts that were assembled at the AWT-hosted workshop on “Shipping Operational Disputes” held in Beijing late last year. Differing opinions were expressed, but it was agreed that it would be preferable to see more definitive language used in charter parties in order to avoid the lengthy debates often associated with this issue.
The discussion then migrated to the actual sources of ocean currents in use today. A panelist with scientific knowledge mentioned that ocean current models have been developed in recent years that can now determine to a great degree of accuracy the direction and strength of the currents on a daily basis. The NCOM model now utilized by AWT in vessel performance assessment takes into consideration actual environmental observations and satellite measured sea levels. This model has shown very good correlation to actual ocean current measurements made by buoys and has a decided advantage over pilot or Admiralty chart data which are based only on long-term averages. With the ability now to establish the daily ocean current effects on a vessel, it is possible to apply these to good weather periods to assess performance. Currents most certainly do affect a ship’s speed; since it is a vessel’s true speed capability that is being determined, it is logical to apply the ocean current model data to arrive at an accurate result.
The workshop panel concluded that this model data could be of significant value to those involved in a dispute. Ocean current model data should be introduced as important material for discussion to assist parties in good faith negotiations to achieve a settlement.
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