The Pirates - the basis of navigation in the 1700's.
All ships were fitted with a compass, which was one of the first instruments used in history to try and maintain some accuracy of location while at sea. Initially using the compass and a simple wooden float on a rope to measure speed, early navigators could gain an idea of where they were going. While not a particularly accurate thing over any distance, it was better than nothing. This method was known as 'dead reckoning'.
The compass was housed in a glass topped case in front of the helmsman so he could keep an eye on his course.
The next development was the backstaff and cross staff and astrolabe, methods to determine a ships latitude by sighting on either the north star, or sun, and determining its height above the horizon. Cross referencing this against tables gave the ships latitude. This method first came into use in 1509, and was pioneered by the Portugese. It would not be replaced by new instruments until 1737, with the octant, and then after again by the sextant.
The navigator kept a log book of the journey, recording his bearing and distances and times. It is amazing to realise that very few sailors could navigate at all. The job was usually undertaken by the captain, and even in the late 1800's this was still the case. In these times, if a captain took his wife with him, she was sometimes taught the skills, whcih saved more than one crews lives.
Maps of the time were not the most brilliant of things, but were of immeasurable value and use. They were obviously hand made and subject to errors. They were no substitue for local knowledge.
Pirates did not use treasure maps as is popularly portrayed in fiction. A couple pirates did bury treasure, but maps were not a feature of pirate life. They were a fictional device long since worked in pirate lore, much as aliens and Egyptian pyramids are forever inseparably associated.
The ships wheel was a new feature on shipping of this time, originally coming into service in 1710 and quickly adopted by everybody. Formerly ships were steered by men on tillers connected to the rudder. In sizeable vessels the tillerman was housed in the stern castle and only had a small space to look out onto the open world. He could not properly see where the ship was going and was directed by the officer on watch. Before him was the compass and a peg board so that he could count the time and direction of travel. The officer kept a close eye on progress and passed changes in course to the tillerman.
On most vessels the job of setting course was undertaken by a specialist officer, for these rules the navigator, or on small vessels by the captain.