Early explorer were able to navigate their ship across the ocean & make map of the coasts they encountered...?

Question

Early explorers were able to navigate their ships across the ocean and make maps of the coasts they encountered. What are two major things that would have helped them?

Answer 1

A GPS system would have helped them a lot

Answer 2

The shoreline is getting smaller (closer to land), I see this at a number of locations on the NJ shore, and places that never flooded before in major storms, now flood immensely. I still am under the mindset that this will happen gradually over the next 50 years, but if you have been here for the last 50, you would know what I mean if you see the areas I'm talking about.

Answer 3

About the only tools were a compass, a sextant, a device to tell speed through the water and some way to keep time. They could detemrine their latitude quite precisely with a sextant but could only guess at longitude. It wasn't until Harrison invented the marine chronometer that they could get any precision in longitude. The longitude of the Americas was not known with great precision until after the transatlantic cable was laid, allowing for synchronized timekeeping between the continents.

Answer 4

The earliest form of navigation was "land navigation" Marine navigation began when pre-historic man attempted to guide his craft, perhaps a log, across the water using a form of piloting which uses familiar landmarks as guides. Dead reckoning was probably next, used to navigate when landmarks were out of sight. While celestrial bodies were used to steer by, celestial navigation, as known today, was not used until the motion of the sun and stars was understood. The voyage of Pythease of Massalia, between 350BC and 300 BC is one of the best records of an early voyage. Use of magnetic compass allowing a course to be maintained. The log and a sand glass could be used to determine distance run. This allowed a dead reckoning estimate of the ship's position to be calculated. When approaching land the lead line was used to assist with landfall. Nautical charts were developed to record new navigational and pilotage information for use by other navigators. The development of accurate celestial navigation for taking lines of position based on the measurement of stars and planets with the sextant allowed ships to more accurately determine position. Most sailors have always been able find absolute north from the stars, which currently rotate around Polaris, or by using a dual sundial called a diptych.

When combined with a plumb bob, some diptyches could also determine latitude. Basically, when the diptych's two sundials indicated the same time, the diptych was aligned to the current latitude and true north.


Compass with rose in centerAnother early invention was the compass rose, a cross or painted panel of wood oriented with the pole star or diptych. This was placed in front of the helmsman.

Latitude was determined with a "cross staff" an instrument vaguely similar to a carpenter's angle with graduated marks on it. Most sailors could use this instrument to take sun sights, but master navigators knew that sightings of Polaris were far more accurate, because they were not subject to time-keeping errors involved in finding noon.

Time-keeping was by precision hourglasses, filled and tested to ¼ of an hour, turned by the helmsman, or a young boy brought for that purpose.

The most important instrument was a navigators' diary, later called a rutter. These were often crucial trade secrets, because they enabled travel to lucrative ports.

The above instruments were a powerful technology, and appear to have been the technique used by ancient Cretan bronze-age trading empire. Using these techniques, masters successfully sailed from the eastern Mediterranean to the south coast of the British Isles.

Some time later, around 300, the magnetic compass was invented in China. This let masters continue sailing a course when the weather limited visibility of the sky.


AstrolabeAround 400, metallurgy allowed construction of astrolabes graduated in degrees, which replaced the wooden latitude instruments for night use. Diptychs remained in use during the day, until shadowing astrolabes were constructed.

After Isaac Newton published the Principia, navigation was transformed. Starting in 1670, the entire world was measured using essentially modern latitude instruments and the best available clocks.

In 1730 the sextant was invented and navigators rapidly replaced their astrolabes. A sextant uses mirrors to measure the altitude of celestial objects with regard to the horizon. Thus, its "pointer" is as long as the horizon is far away. This eliminates the "cosine" error of an astrolabe's short pointer. Modern sextants measure to 0.2 minutes of arc, an error that translates to a distance of about 0.2 nautical miles (400 m).

At first, the best available "clocks" were the moons of Jupiter, and the calculated transits of selected stars by the moon. These methods were too complex to be used by any but skilled astronomers, but they sufficed to map most of the world. A number of scientific journals during this period were started especially to chronicle geography.

Answer 5

The stars was a major thing the navigate.

Answer 6

A Global Position System and a sattelite telephone would have helped them emmensly.

Answer 7

Compasa and Star constelation

Answer 8

Knowledge of the stars/constellations in the sky.

Answer 9

Compasses and maps, but they were the people who sort of made the maps...

Answer 10

Hi. A compass and a sextant.