Logbook (nautical)

The term originally referred to a book for recording readings from the chip log that was used to estimate a ship's speed through the water.

Today, a virtual or electronic logbook is typically used for record-keeping for complex machines such as nuclear plants or particle accelerators.

Most national shipping authorities and admiralties specify that logbooks are kept to provide a record of events, and to help crews navigate should radio, radar or the GPS 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" is used on airplanes.

Logbook entries are sometimes of great importance in legal cases involving maritime commercial disputes.