If it is decided to enrol the ship with such a service for a particular voyage, the Master will give the service the details of the intended voyage and they will respond with their recommended best route. As the voyage proceeds, the Master regularly reports to the service giving his position and the weather he is experiencing. This information, combined with similar reports from other ships in the vicinity, enables the service to amend their advice if this proves appropriate. It is not at all unusual for the recommended route to be longer in miles than a direct route but in terms of time taken, fuel consumed and damage avoided, the routing service’s recommendations should always prove preferable. These services are, after all, doing what any sensible Master does naturally but the routing services have the advantage of having available far more weather information supported by satellite observations. A practice becoming prevalent now is for time charterers to insist upon the ship enrolling with a routing service for every voyage in order to have an independent check on the Master taking the most expeditious course. One advantage of this to both sides is that it provides independent evidence should there be arguments about speed and consumption which are usually based on ‘fair weather’. Apart from such specific attention to the weather through the use of experts, all ship managers should ensure they have a good background knowledge of elementary climatology. For example ice closes the Great Lakes and the St. Lawrence Seaway during winter months and a close watch has to be kept on a ship’s position if she is venturing into such areas late in the season. Legal arguments as to whether a ship is off-hire or on-hire while trapped for several months are futile if the time charterers have gone bankrupt in the meantime.