Maritime navigation in the past and today


Long before computers were invented, the world was discovered by the first sailors – Vikings and Polynesians. How did they find direction in the open ocean?

Determining your location in the open sea is not easy, and without modern equipment, the task is even extremely difficult. On-board computer systems have fallen out of service for days due to virus attacks. In some cases, ships drifted aimlessly  for even weeks because there was no cybersecurity specialist on board to fix the problem.

How the first sailors crossed the oceans

The Polynesians were great sailors. Several hundred years before Christopher Columbus' expedition across the Atlantic, the Polynesians crossed the Pacific on their wooden canoes, covering thousands of miles between the islands of the so-called polynesian triangle. They used the sun, stars, moon, wind and currents to determine their orientation. They also created special charts  from sticks and seashells.

The Vikings also traveled thousands of miles between Northern Europe, the British Isles, Iceland, Greenland, and even North America. They were helped by calculations and careful observation: they drifted, watched the whales, and took trained ravens on board to search for the nearest land.

According to various sources, to determine their position on the ocean, Vikings-travelers used the sun compass, counted the days on the ocean, estimated the speed of the ship, as well as the position in relation to the sun and stars. Some believe they even used sunstones that polarized the light, making it possible to determine the solar azimuth in unfavorable weather (when the sun and stars were invisible).

Vikings often relied on intuition and inaccurate conclusions. In stories about them, you hear about travelers tormented by fog or bad weather. Under such conditions, the ancient seafarers completely lost their sense of direction.

The fight for longitude

As far as we know, the idea of ​​using coordinates first appeared in ancient Greece around 200 BC. Claudius Ptolemy was the first to systematize the  concept of latitude and longitude .

The sailors used charts of the Earth and the sky and a coordinate grid to determine their location. However, these coordinates were not so easy to find. While the sun, moon, and stars might have helped determine the latitude, longitude was far more difficult.

Longitude can be calculated as the difference between the local time and the time at a given reference point measured at the same moment. Accuracy is essential: at the equator, the degree of shift is 68 miles. Time on board could be determined using the sun and the stars, but the clocks were not very accurate back then. Moreover, people could not tell the time at home port or the Prime Meridian, Greenwich. Therefore, for many years, the most important task of seafarers was to learn how to determine longitude.

Between the 16th and 18th centuries, the greatest maritime powers: Spain, the Netherlands, Portugal, Venice and England announced a competition to invent a simple and practical way to accurately determine the longitude of a ship at sea. The British government offered £ 20,000, the equivalent of today’s £ 2.6 million, or around £ 3.8 million in 2015. John Harrison went to the largest share of the prize money for inventing the marine chronometer . this tool entered general use in 1760.

Earlier, in 1757, the sextant was invented (several scientists worked on it simultaneously, including Isaac Newton, John Hadley, and Thomas Godfrey). Both tools finally solved the puzzle of accurately determining longitude at sea.

How did these devices work? At noon, the sailor measured the angle between the horizon and the sun with a sextant and compared it with Greenwich Central European Time, shown on a chronometer. Then ships could determine their longitude – how far the ship sailed east or west of the meridian.

What is used today?

Today, most ships rely on electronic chart and navigational information ( ECDIS ) imaging systems and the Global Positioning System ( GPS ).

To determine your exact location, GPS uses a network of over 30 satellites. Initially, this system was used for military purposes, but today it is used by almost everyone – from tourists, to sailors, to airplane pilots.

In addition to GPS, ships also began to use electronic maps. This allows sailors to spend minutes rather than hours on basic activities such as plotting and correcting flow routes. Watch officers can spend more time observing and analyzing their surroundings: weather, ship speed, and other important variables. It all adds up to increasing the safety of your voyage.

As in aviation , marine ECDIS systems must be properly secured. If a ship wishes to abandon paper maps, it needs two ECDIS devices with separate displays and a database.

In the case of Murphy’s Law …

It is possible for both ECDIS systems to fail due to, for example, a programming error or a targeted attack. Computer systems also stop running smoothly when installing patches and updates. In turn, researchers regularly discover gaps in key technologies such as ECDIS, GPS and the marine Automatic Identification System (AIS). They are patched, but there are still new bugs.

The navigation system error is not deadly near the coast: you can expect help, you can see orientation points, and usually your internet and cellular connections are working. If a seafarer observes any problems, he may contact a designated person ashore and request a PDF sea chart with shoals, currents and hazardous places marked on it.

The GPS system is also imperfect. Electromagnetic radiation from the sun can have a big influence  on the performance of satellites. In addition, criminals (pirates or terrorists) can block the signal using a simple, inexpensive and readily available GPS jamming device .

A hacked GPS system  can turn the ship off course, making the whole situation less suspicious. At best, the ship will be delayed – and at worst, it will face a catastrophe or collision. To avoid such situations, the US Navy teaches officers to navigate by the sun and stars .

The most obvious threat that can force modern deck officers to refresh their astronavigation skills is lack of connection or GPS signal blockage in open space. of course, seafarers also have unofficial methods of determining their location: for example, in an embarrassing situation, they can download GPS coordinates to their smartphones. They actually do this when they want to pinpoint the ship’s location and don’t want to leave the cabin. It is difficult for modern ships with motors and generators to get lost in the open water.

But if you don’t have electrical equipment, it’s hard to navigate. There was an incident two years ago that clearly shows how much we have achieved in sailing and navigation in the last few hundred years. In 2014, an ultramarathon runner attempted to run from Florida to Bermuda  in a „hydropod” (an inflatable vessel resembling a hamster wheel; it moves when a person runs). The man was fit, his ship could not sink, but he forgot about navigation. Reza Baluchi did not stray too far from the shores of Florida and got lost; however, he managed to ask a passing vessel to indicate the direction to Bermuda.