The objective of this paper is to study the possible use of meteo-marine forecasts for correct management of ships' ballast water, in order to improve the safety of navigation, having due consideration to the economical costs (wrong load/unload of water) and the possible performance impacts that could be generated. The analysis has been carried out verifying the operative forecasts used for crew training in the Italian yacht Consorzio Prada for the America's Cup 2000 and issued in the period April–July 1999. Studying the forecasts' quality, situations of potential incorrect load of ballast water have been examined together with the potential negative effects. It has been demonstrated that an accurate weather forecast is of paramount importance to safe navigation without economic loss while recognising the related performance aspects.