The Capestang bridge over the Canal du Midi at PK 189 at Capestang is a very important structure for those wishing to motor on the canal. It is used as a measuring device as it is the lowest structure on the canal. A boat, with an air draft under 3.3 m (11 ft) at the center and assuming a beam no more than 5 m (16 ft), a height of no more than 2.4 m (7.9 ft) at the extremities, should make it under the bridge. A British boat builder who builds boats for several of the boat hire companies in France builds their boats to meet these requirements.