Turning basin

A turning basin or swinging basin is a wider body of water, either located at the end of a ship canal or in a port to allow cargo ships to turn and reverse their direction of travel, or to enable long narrow barges in a canal to turn a sharp corner. 
For a complete 180-degree turnaround, the width of the basin must be more than the length of the longest vessel normally traversing the waterway. Onboard bow thrusters or tugboats may assist in manoeuvering the ship. 