A logbook (a ship's logs or simply log) is a record of important events in the management, operation, and navigation of a ship. It is essential to traditional navigation, and must be filled in at least daily. The term originally referred to a book for recording readings from the

chip log A chip log, also called common log, ship log, or just log, is a navigation tool mariners use to estimate the speed of a vessel through water. The word ''knot'', to mean nautical mile per hour, derives from this measurement method. History All ...

that was used to estimate a ship's speed through the water. Today's ship's log has grown to contain many other types of information, and is a record of operational data relating to a

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

, such as weather conditions, times of routine events and significant incidents,

crew A crew is a body or a class of people who work at a common activity, generally in a structured or hierarchical organization. A location in which a crew works is called a crewyard or a workyard. The word has nautical resonances: the tasks involved ...

complement or what

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

s were docked at and when. The term ''logbook'' has spread to a wide variety of other usages. Today, a virtual or electronic logbook is typically used for record-keeping for complex machines such as nuclear plants or particle accelerators. In military terms, a logbook is a series of official and legally binding documents. Each document (usually arranged by date) is marked with the time of an event or action of significance.

Shipping

Most national shipping authorities and admiralties specify that logbooks are kept to provide a record of events, and to help crews navigate should

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

or the

GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...

fail. Examination of the detail in a ship's log is often an important part of the investigative process for official maritime inquiries, in much the same way as a "

black box In science, computing, and engineering, a black box is a system which can be viewed in terms of its inputs and outputs (or transfer characteristics), without any knowledge of its internal workings. Its implementation is "opaque" (black). The te ...

" is used on

airplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spe ...

s. Logbook entries are sometimes of great importance in legal cases involving maritime commercial disputes. Commercial ships and naval vessels often keep a "rough log", – or "scrap log" – a preliminary draft of the ship's course, speed, location, and other data, which is then transcribed as the "smooth log", – or "official log" – the final version of the ship's record. Changes may be made to the rough log but the smooth log is considered permanent and no erasures are permitted. Alterations or corrections in an official logbook must be initialled by the authorised keeper of the logbook and the original data entries which have been cancelled or corrected must remain legible.

In fiction

* The '' Hornblower'' series mentions logs to explain plot development, or to make the story more realistic. * In ''

Star Trek ''Star Trek'' is an American science fiction media franchise created by Gene Roddenberry, which began with the eponymous 1960s television series and quickly became a worldwide pop-culture phenomenon. The franchise has expanded into vari ...

'', the captain's log, a form of ship's log, is used to fill in the audience as to the events in progress, and acts as a

diegetic Diegesis (; from the Greek from , "to narrate") is a style of fiction storytelling that presents an interior view of a world in which: # Details about the world itself and the experiences of its characters are revealed explicitly through narra ...

form of soliloquy. This is part of a larger log system that includes personal logs (a sort of journal) and other officers' official logs, for stories that could not believably be reflected in the official Captain's log.

References

{{Authority control Navigation Maritime books Records management

Shipping

In fiction

See also

References