Before embarking on an open-ocean voyage, planning and preparation will include studying charts, weather reports/warnings, almanacs and navigation books of the route to be followed. In addition, supplies need to be stocked (including fresh water and fuel), navigation instruments checked and the ship itself needs to be inspected and the crew needs to be given exact instruction on the jobs are expected to perform (e.g. the watch, which is generally 4 hours on and 4 hours off, navigation, steering, rigging sails, ...). In addition, the crew needs to be well trained at working together and with the ship in question. Finally, the sailor must be mentally prepared for dealing with harsh situations. There have been many well-documented cases where sailors had to be rescued simply because they were not sufficiently prepared (the sailors as well as the ship) or lacked experience for their venture and ran into serious trouble.