Build canals and locks.
2.0.1 alpha 17 or later
Configuration file: canals on|off
Command line: -Xl
You build canals and locks with the "buy land" (picture 1) tool from the docks menu. Locks are built automatically on slopes and allow the ships to access the higher levels of water.
Picture 1: build canals with the buy land option
This is how the canals look like when you build them on slopes (will create locks)
Picture 2: canals with locks (Graphics by George)
This feature was contributed by Oskar Eisemuth.