The Ocean Virgo 
The Commercial Court, via “The Ocean Virgo”  940 LMLN 1 case, held that an admissible period of good weather need not be a period of 24 consecutive hours running from noon to noon, provided the governing charter party agreement did not stipulate otherwise. The Commercial Court also acknowledged that an arbitration tribunal was within its right to determine whether or not a total good weather period was sufficient to accurately represent a vessel’s true performance. The Commercial Court offered the following rationale:
“In the court’s judgment, the tribunal erred in law when it directed itself that an admissible period of good weather had to be a period of 24 consecutive hours running from noon to noon. The charterparty merely referred to “good weather”. There were no words in the charterparty which justified construing good weather as meaning good weather days of 24 hours from noon to noon.
However, the owners were right to say that the tribunal had also excluded the periods of good weather relied upon in the second leg of the ballast voyage and in the laden voyage because they were too small a sample. That was not an error of law; it was an approach to the assessment of the evidence which the tribunal was entitled to take. Thus, even if the tribunal had not made the error of law with regard to “a good weather day of 24 hours from noon to noon” it would still have held that the periods of good weather in: (a) the second leg of the ballast voyage; and (b) the laden voyage were too small a sample to be representative.”
To summarize, the Commercial Court has told us, via “The Ocean Virgo,” that while a tribunal cannot subjectively determine the minimum allowable duration of an individual good weather period, the tribunal is within its right to determine whether or not the good weather period for a given voyage is sufficient for assessing a vessel’s performance.