Rutter (nautical)

A rutter is a mariner's handbook of written sailing directions. Before the advent of nautical charts, rutters were the primary store of geographic information for maritime navigation.

It was known as a periplus ("sailing-around" book) in classical antiquity and a portolano ("port book") to medieval Italian sailors in the Mediterranean Sea. Portuguese navigators of the 16th century called it a roteiro, the French a routier, from which the English word "rutter" is derived. In Dutch, it was called a leeskaart ("reading chart"), in German a Seebuch ("sea book"), and in Spanish a derrotero.

History

Before the advent of nautical charts in the 14th century, navigation at sea relied on the accumulated knowledge of navigators and pilots. Plotting a course at sea required knowing the direction and distance between point A and point B. Knowledge of where places lay relative to each other was acquired by mariners during their long experience at sea.

The earliest peripluses of classical antiquity were not necessarily written as practical navigational handbooks. Some were more akin to an adventure travelogue, to celebrate a famous voyage. Others were disguised as such, notably the Periplus of Pseudo-Scylax from the 4th century BCE, which described the harbors and landmarks along the north African coast west of the Nile Delta.