Category: Navigation

Introduction An autopilot keeps a ship on a set course without a helmsman at the wheel. It is used when a ship has to steer one course for a long time. Any deviation is controlled electronically and automatically, so the officer of the watch can concentrate on lookout and navigation. This article explains how the…

Introduction The gyrocompass is a north-seeking compass. It works on the principle of the gyroscope, altered so that the gyroscope seeks north. Unlike a magnetic compass, it shows true heading, so it is not affected by magnetic variation or deviation. Principle of the Gyroscope The principle of the gyroscope is the law of conservation of…

Introduction The rate of turn indicator (ROTI) shows the instantaneous rate of change of the ship’s heading. It is connected to the steering repeater, which feeds it at a rate of 60 to 200 pulses per minute. The rate of turn (ROT) is measured in degrees per minute (°/min). As per the IMO standard, the…

Introduction The echo sounder is a bridge instrument that measures the depth of water under the ship’s keel. It is fitted on ships as required by SOLAS Chapter V. It is most important to monitor it during coastal navigation and whenever approaching shallow patches, to make sure the ship has enough water underneath to pass…