What do ships use to navigate

The lateen sails of these ships were able to sail toward the wind and provided speed. In , Christopher Columbus used this type of vessel for his first voyage. According to Columbus' logs, he mainly used dead reckoning navigation. Dead reckoning was a method in which the navigator would measure the distance and course from a specific point, such as the port. He would mark the day's ending point on a chart, and this point would serve as the starting point for the next day.

Dead reckoning didn't determine the ship's latitude. To do this, Columbus used celestial navigation, which is basically using the moon, sun, and stars to determine your position. Other tools that were used by Columbus for navigational purposes were the compass, hourglass, astrolabe, and quadrant. The latter was a tool that measured latitude by determining the angle between the sun or a star and the horizon. Navigating during sea voyages nowadays is a lot easier than back then.

In later years, compasses used iron needles, which were magnetised by striking them with a lodestone. By in Medieval Europe and the Islamic world, dry compasses started to emerge, replaced by liquid-filled magnetic compasses in the 20th century. Still used today, a compass rose is a design on a compass, map, nautical chart, or monument used to display the orientation of North, East, South, and West, as well as their intermediate points.

Before compass roses were used on maps, lines were drawn from central points. These lines were hard to follow since there were so many lines intersecting each other on one map. The rose design was typically drawn in a way that made it easier to follow the directional lines. The log line is an old instrument for measuring the speed of the ship.

It consisted of a flat piece of wood which was weighted at the bottom edge to enable it to float upright in the water. The log was attached a long rope. The log line was wound on a spool so that it could be reeled out after the log was thrown into the water at the aft of the ship. The friction of the water held the log in place as the ship sailed away from it. Most modern ships have satellite navigation systems such as GPS or other navigation tools that transmit data to the built-in gyro compass computer for correction.

Based on the processed data, ECDIS displays maps and the location of the vessel, plots the route and monitors deviations from the planned route, calculates safe courses, warns the navigation officer about danger, keeps a ship's log and provides many other sophisticated navigation and safety functions.

Thus, ECDIS significantly reduces the burden on the navigator, which frees up time for better monitoring of the surrounding circumstances and making informed decisions on ship management. With the help of radar, any target around the vessel can be detected: ships, land obstacles, icebergs, etc. For this purpose, a rotating antenna is used. This data can be used to avoid collisions and is especially useful in adverse weather conditions.

There are 2 types of radars used on ships: X-band and S-band radars. X-band radar operates at a frequency of about 10 GHz and with a wavelength of 3 cm smaller antennas in weight and size. Being of higher frequency, this band provides a better target resolution. The S-band radar operates at a frequency of 3 GHz with a wavelength of 10 cm a larger antenna on the mast. This band is more resistant to interference than the X-band, and provides more accurate data during heavy rain or snow.

ARPA Automatic Radar Plotting Aid is a computer system that processes radar data and creates tracks for vessels within the radar coverage of the ship. Using advanced technologies, ARPA not only represents the current situation, but also predicts future situations. The system calculates the course of the tracked objects, their speed, time and distance necessary for safe passage with other vessels.

If necessary, the user can get more detailed information on selected targets. This allows the officer of the watch to plan a safer course without collisions. This is a system electronic or hydraulic designed to automatically control the steering mechanism of a vessel and maintain it on a set course. By holding the steering in autopilot mode, the navigator can focus on other critical tasks such as collision risk assessment and avoidance.

The device is synchronized with the gyro compass. If the latter has any malfunctions, they will affect the steering of the vessel. In case of gyro compass failure, the system will lose the ability to control the vessel. Modern autopilot systems can also be synchronized with ECDIS, which allows them to follow the route laid out on the electronic chart. Autopilot cannot completely replace a human. The vessel must be operated manually when navigating in restricted waters and high-density traffic areas.

Unlike magnetic compass, gyro compass is not hampered by an external magnetic field. Its repeater system must be present in the steering platform for emergency steering. Read more about Gyro Compass here. The seagoing vessels depend on S-band and X-band frequency radar system for navigation as it can detect targets and display the information on the screen such as the distance of the ship from land, any floating objects an island, rocks, iceberg etc.

It is a rotating antenna which discovers the surrounding area of the ship. The magnetic compass work in conjunction with the magnetic field of the earth and is the essential means of the direction indicating device. It is used to get a planned course for the voyage. This ship navigation equipment is usually fitted at the centre line of the ship on the monkey island. A transmitting magnetic type compass is fitted so that the output can be displayed in the bridge panel.

The ship bridge layout is filled with equipment and tools used for navigation. The autopilot is considered to be one of the most effective bridge navigational equipment as it assists the human operator in controlling the ship by keeping the steering in autopilot, which allows them to concentrate on broad aspects of the operation.

Automatic Radar Plotting Aid displays the position of a ship and other vessels nearby. The radar displays the position of the ships in the vicinity and selects the course for the vessel by avoiding any kind of collision. It also presents them as vectors on the display screen and constantly update the parameters with each turn of the antenna by calculating their nearest points of approach to own ship and also the time before this will occur. Just like ARPA, automatic tracking aid displays the information on tracked targets in graphic and numeric to generate a planned layout for a safer and collision-free course.

Usually, A large size target measuring m or more in the circumference is considered as a landmass and not tracked. Echoes less than m are deemed as targets to be tracked. This bridge equipment on a ship is used to measure the speed and the distance travelled by a ship from a set point. By calculating the same, ETA of the ship is adjusted or given to the port authority and agent. There are many modern ship navigation tools present on ship and echo sounder is one of the instruments which has been in the play from almost years now.

ECDIS is a development in the navigational chart system used in naval vessels and ships. AIS is also among the types of a navigation system which helps to pinpoint the location and other navigational statistics of ships. AIS uses VHF radio channels as transmitters and receivers to send and receive messages between ships which endeavours to fulfil a lot of responsibilities. Read more about AIS here. LRIT is an international tracking and identification system incorporated by the IMO under its SOLAS convention to ensure a thorough tracking system for ships of gross tons and above which are on international voyages across the world.

This maritime equipment is fitted to improve the maritime domain awareness. Read more about LRIT here. Rudder angle indicator, as the name indicates, provides the angle of the rudder. The display is provided on the navigation bridge equipment console so that the ship navigation officer can control the rate of turn and rudder angle of the ship. The indication is also provided in the bridge wing and engine control room.