On the West side of Ostend another canal, the "Old Haven", was more of a defensive moat which was barely navigable but could not be easily waded except for four hours at low tide. A ditch passed between the old and new towns, which were connected by bridges, and round the new town, parallel to the "Geule" on one side, and to the old harbour and Yperlet stream on the other. The "Guele" itself had ramparts and bulwarks on one side, and a counter scarp with ravelins on the other, while the water level for both canals could be adjusted from the lock located in the city.