Navigation System

In this article we explore some of the key advances since the days of paper charts and sextants that are keeping modern ships safe from catastrophic accidents.

The officer of the watch on the bridge of a modern cargo ship or cruise liner is responsible for the safe navigation of these giants of the sea. They rely on an array of navigational technology to safely find their way and avoid collisions with other ships or natural obstacles. But how has navigational technology advanced in the past 50 years?

“Steady as She Goes” – Navigating a Ship 50 Years Ago

Even in the 1960s and 1970s, ships already had some impressive modern technology available. The increasing accuracy and reliability of gyrocompasses had made error-prone magnetic compasses obsolete except as a backup. Gyrocompasses rely on a rapidly spinning gyroscope to detect the rotation of the earth and point towards the centre of rotation at the North Pole.

The widespread use of radar onboard ships, originally developed for military application started to find application in civilian ships from the 1940s. This was a major advance allowing ships officers to effectively see in the dark or even in thick fog or low cloud. Later, Automatic Radar Plotting Assistance was added to help make sense of complex traffic situations by keeping track of objects the radar had picked up.

VHF radio was widely adopted and allowed ship-to-ship and ship-to-shore voice communication, replacing signal flags and semaphore. To fix the ship’s position, radio direction finding was used. Hyperbolic radio-fixing systems such as LORAN-A and DECCA were considered the state of the art in navigational technology. By triangulating the bearing of radio signal transmitters at known locations, the ship’s navigator was able to fix the ship’s position down to the accuracy of approximately one nautical mile, even in the open ocean. These radio-fixing aids simplified the navigator’s problem of determining how far from land the ship was but did not do much for precise coastal pilotage. Skilled local pilots with the ability to steer the ship from visual marks with knowledge of local currents and hazards remained critical to safe navigation.

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Canadian navigation solution provider OSI Maritime Systems (OSI) has been contracted to provide the integrated navigation system for mid-life modernization (MLM) of Bung Tomo-class multi-role light frigate (MRLF).

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