Ocean currents can have a considerable effect on some voyages; a vessel may steam against a 2 to 3 knot current for a number of days with a resulting loss of performance. Equally, the vessel may have the benefit of the same current if she performs the same passage on return. There is little or no authority from the courts on the subject so London arbitrators will adopt differing views. There are examples of where they have ignored currents entirely when the only relevant provision has been that the vessel’s performance is measured in good weather. On other occasions current factors may be accepted with the resultant increase or deduction in speed and consumption applied. Perhaps, as a rule of thumb, current factors are most likely to be applied when a specific voyage or short number of voyages are performed and where they are likely to have a material effect. However, if the performance is being reviewed over a long period or there are a number of varied passages the current factor will be taken as neutral and not applied.