Before revision: The last significant free-running (undammed) section of the Columbia River in the US A map of the reaches of the River Thames; it can be seen that a reach is a straightish stretch (and can therefore be sailed in one reach, straight-line path between tacks, unless the wind is too close to head-on to allow the sailing-boat to reach A reach may also be an expanse, or widening, of a stream or river channel.
After revision: Thames barges reaching on the Thames (race)The last significant free-running (undammed) section of the Columbia River in the US A map of the reaches of the River Thames; it can be seen that a reach is a straightish stretch (and can therefore be sailed in one reach, straight-line path between tacks, unless the wind is too close to head-on to allow the sailing-boat to reach A reach may also be an expanse, or widening, of a stream or river channel.