Dikes and Ditches by Oliver Optic

The pilot of the ship was discharged at eight o'clock in the evening, and the two vessels stood on their course to the northward, with a fresh breeze from the south-west. They kept just outside of the continuous chains of shoals on the coast, but for nearly the whole time within sight of the numerous lighthouses which mark the various entrances of the Scheldt and the Maas. The masters on duty were kept very busy in consulting the charts and the sailing directions; but at one o'clock the squadron was off the Brielle Gat, which is the deepest entrance to the river.

There are two principal passages by which vessels may reach Rotterdam from the sea. At the mouth of the Maas, or of the river which includes the Rhine, Waal, and Maas, there is a large island called the Voorne. At the north of it is the Brielle Gat, which is the most direct sea passage to the city; but the bar at its mouth has only seven and a half feet of water at low tide. At the south of the island is the Goeree Gat, by which the largest ships must enter, passing through the island in a canal.