What is the main purpose of the Engine Order Telegraph (EOT)?

The main purpose of the Engine Order Telegraph (EOT) is to communicate major speed changes between the bridge and the engine room of a vessel. This device allows the officer on duty at the bridge to send commands regarding the desired speed and direction of the ship's engines to the engineers in the engine room. The effective operation of an EOT is crucial for maintaining safe navigation and ensuring that the ship can respond appropriately to various conditions on the water.

Using an EOT allows for a standardized method of communication that minimizes the chances of miscommunication, which can be vital during critical periods of navigation or maneuvering. The clarity it provides in transmitting commands is essential for the coordinated operation of the vessel, especially in busy or complex maritime environments. Other options, such as controlling engine power supply, monitoring fuel levels, or determining water depth, do not fall under the primary function of the EOT.