After the dam was finished the lock was made. Only by this lock ships could go from one side to the other. Not only fishing boats but also vessels with special and extreme large equipment and materials for the construction of the Brouwersdam must pass this lock. This lock needed to be large and had a length of 125 meters and a width of 16 meters. To calculate the depth of the lock was not easy but finally they made the bottom of the lock 6.5 meters below NAP.