Basin

A wet dock into which ve els enter from the river before their admi ion through interior gates to the principal dock, and vice vers a with ships leaving the main dock, on their way through the basin to the river •, with which the water of the basin is put in connection by opening its outer gates, usually about two hours before high water for the pa age of incoming and outgoing ve els. At high water these outer gates are closed, and remain shut till nearly the following high water; thus permitting communication between the basin and the main dock by opening the inside gates; the usual water level being so maintained.