Fresh water set an age-of-sail ship's range

How was the range of an age-of-sail warship measured?

By how long its food and fresh water would last and where it could replenish them; long voyages therefore relied on islands and coastal stops.

A sailing ship's endurance was measured through provisions rather than fuel. Salted food could be carried in quantity, but crews still needed fresh water and vegetables, so long routes depended on islands and coastal resupply. An ocean passage was also a logistical chain of replenishment points.