A simple crane that was frequently used in quarries, docks and boatyards. They are also called stiff-leg derricks. The difference between a crane and a derrick is that the jib (arm) can be raised or lowered on a derrick, rather than the jib remaining stationary. They were used for lifting and moving heavy loads, larger ones had control cabins and they were usually steam-powered. The Thames Path bears right here, just before the derrick, onto Odessa Street.