While the lock of Ericson remained in use, the sea traffic continuously increased and in the 1920s more than 25,000 ships used it annually. Its dimensions soon proved insufficient and a shipyard located upstream had to build its ships in two pieces, tow them through the lock to assemble them in a second yard downstream. The working length was eventually increased by adding to secondary gates which lengthened the dock from 45 meters to 58,6 (using one of the gates) and 70,45 meters (using both) respectively. Today the lock of Ericson is superseded by the fourth lock, it is still in existence under the statue of Charles John, in spring much needed as a spillway for the annual spring flood discharge.