Good weather sampling and extrapolation
The two-stage method for proving underperformance: qualifying periods, the rival calculation methods, the weather factor, and extrapolating across a voyage.
Good weather sampling is the standard method of proving a breach of a speed and consumption warranty. Stage one tests the vessel’s performance against the contractual yardstick in periods satisfying every limb of the good weather definition; stage two extrapolates the shortfall across the whole voyage, on the inference that a vessel underperforming in good weather will not perform as warranted in bad.
The method is primary where a good weather warranty is agreed but not exclusive, and at least two rival calculation methods both claim The Didymi while producing materially different figures. The full article will set out each method with its arithmetic, the treatment of charterers’ ordered slow steaming and off-hire periods, the weather factor and when a tribunal will accept one, and the cases in which strict extrapolation was declined.