Vrangfoss is the largest lock complex on the Bandak Canal with five locks and a lift of 23 metres. Before canalization, Vrangfoss was about two kilometres long with a fall of 25 metres through a narrow rock passage flanked by high overhanging walls. Vrangfoss was the cause of nearly insurmountable problems for loggers and takes its name from this (vrang = contrary, troublesome). It was said that logs could remain stuck in Vrangfoss for several years, that it was often not possible to loosen the old logs before new ones were brought in, and that up to 14 persons were employed year round to loosen the tangled logs.
The friction sometimes caused fires. During the construction of the canal between 1887-1892, a 32-metre high dam with a 21-metre wide base was added to the five locks. This dam held back water as far as Lunde, raising the water level about two metres.
The lower Vrangfoss Canal is shielded from the falls and lined with a stone breakwater, sheltering the entrance into the canal.
Chiseled into the rock wall up above the lower canal is the monogram of King Oscar II, and athere is a full-scale replica of the old wooden bridge across Eiebekken.
For years, tourists have enjoyed stopping at the lookout point on the lower canal. The canal saw is still in place and is used to cut the custom-sized timber needed for maintenance of the lock gates. Made after the last war, the saw is positioned so that timber can be drawn directly either from the lower canal or from land. Vrangfoss Bridge is a simple-span beam bridge built in 1958. Close to the locks there is a distinctive and very beautiful park with large deciduous trees and conifers, footpaths, lookout points, and a smithy and guardroom built during the early days of the canal.
At the upper part of the Vrangfoss locks we see the lockkeeper´s residence with its distinctive long veranda.
Located at the upper lock chambre is the little guardroom in Swiss style with slate shingles. Traffic was monitored from this little building. On a rock at the upper end, the names of King Oscar II and Prince Eugen are inscribed as a memento of their visit to Vrangfoss on October 29, 1893. Vrangfoss power station is located inside the mountain near the dam.
THE BANDAK-NORDSJØ CANAL
Also called the Bandak Canal, was built between 1887 and 1892. The idea of building a canal between Ulefoss and Strengen was the brainchild of Axel Borchgrevink, manager of the Norsjø-Skien Canal, and Sætren, one of the directors. Fourteen locks were built along the 17 kilometres of canal between Ulefoss and Strengen, giving a total ascent of 57 metres (over 150 feet). The locks at Vrangfoss Falls are most impressive and, in the words of Teknisk Ugeblad (Technical Magazine) in 1892: "a work of art which will bear perpetual witness to the skill of our engineers; it is this feat of engineering that will to the traveller be most fascinating and memorable". The construction of the locks at Vrangfoss Falls and Hogga was both difficult and dangerous, but by June 1891, the canal was navigable by steamboat. The official opening took place on September 20, 1892.