Vlotbrug

Vlotbrug(plural,Dutch:vlotbruggen) translates from Dutch into English as "raft bridge". It is a special kind of floatingRetractable bridgesat the Great North Holland Canal which pivot either centrally or from one or both banks of a body of water to allow vessels to pass through.

In theDutchprovince ofNorth Holland,a vlotbrug is aretractablepontoon bridge which opens for water traffic by retracting in its long direction, with the roadway sliding under fixed structure(s) oncanalbank(s). This article relates to bridges of that design. In the eastern Netherlands, a name for that design of bridge wasscholle.

An animation of the generic mode of operation ofretractable bridges.

Burgervlotbrug closed

Burgervlotbrug opening

Burgervlotbrug opening II

Burgervlotbrug open

History and design

TheNoordhollandsch Kanaalin North Holland was constructed 1820-1824. Many vlotbruggen were built across it at that time. For an uncertain reason, it was not possible to build known types of opening bridges such asdrawbridgesinstead.The apparent lack of earlier references suggests that the vlotbrug may then have been a novel idea.

One old, undated, photograph (see theGallery,below: De Scholle,Vroomshoop,Overijsselprovince, eastern Netherlands) shows a canal withjettieson both banks connected by a moveable roadway. The roadway is wooden, is equipped with guard rails, and has upwardly-sloping portions at each end which communicate with the fixed structures. The horizontal part of the roadway is roughly 1 m (3 ft) above the water. The exact method of operation is unclear; for example, as to whether the roadway was moved by manpower or by draught animals, and as to whether the roadway was pulled up onto a jetty or was slid underneath a jetty, on water. It is also unclear whether the roadway had additionalflotation devices.The roadway may have been simply a modified rectangular boat of thepunttype (Dutch:vlet).

The names of the modern villagesBurgervlotbrugandSint Maartensvlotbrugin North Holland suggest they may have been new settlements around a vlotbrug. They are close to the previously existing villagesBurgerbrugandSint Maartensbrug.The names of the neighbourhoodsStolpervlotbrug,nearDe Stolpenin North Holland, and ofVlotbruginHellevoetsluisandTweede VlotbruginNissewaard,both inSouth Hollandprovince, may have had similar origins.

More recent photographs and videos of vlotbruggen are clearer than the old photograph of De Scholle at Vroomshoop. The first vlotbruggen were of wood. Modern bridges are of steel, and are operated mechanically. The roadway is divided into two in the middle of the waterway, and its two sections withdraw under fixed structures on either side. The bridges have safety features such as moveable barriers which block the roadway to land traffic, andtraffic lightsand sound signals to alert both land and water traffic. They are equipped withfendersbased on piles driven into the canal bed, to protect the fixed structures against accidental damage from watercraft.

The vlotbrug design is not without risk of accidents, especially since the introduction of motorised vehicles. Both land and water vehicles have been involved. In the 1960s or 1970s, the vlotbrug at Sint Maartensvlotbrug was damaged while a lorry was crossing. It has been said that the lorry was overloaded.In 1988, the vlotbrug at't Zandwas damaged when a lorry toppled over while crossing it.In 1999, the vlotbrug at Burgervlotbrug was damaged when a heavily laden lorry attempted to cross it. Repairs took several months.After an accident in 2012 at Burgervlotbrug (for which theskipperof ariver bargewas blamed), it was asked whether or not vlotbruggen have a place in the 21st century. Opinion was divided.In 2017, the vlotbrug at Burgervlotbrug was damaged when a freighter collided with one of thefendersprotecting the bridge.

Operating vlotbruggen

As of 2017,five operating vlotbruggen exist, all crossing the Noordhollandsch Kanaal in North Holland. From south to north (i.e. in the seawards direction):

• Koedijkervlotbrug,Koedijk,Alkmaar
• Rekervlotbrug, Koedijk, Alkmaar (named afterRekere,a former river which is now part of the Noordhollandsch Kanaal)
• Vlotbrug,Burgervlotbrug,Schagen
• Vlotbrug,Sint Maartensvlotbrug,Schagen
• Vlotbrug,'t Zand,Schagen

Rekervlotbrug was built in 2010. Because of technical problems, it was not brought fully into service that year.The other four bridges are modernised versions of ones built in the 19th century. Koedijkervlotbrug is open only to pedestrians and cyclists. The others accept some mechanised vehicles also.

Gallery

North Holland

• 
  Vlotbrug, Heiligland, Alkmaar (1919)
• 
  Koedijkervlotbrug, Koedijk, Alkmaar
• 
  Koedijkervlotbrug, Koedijk, Alkmaar
• 
  Rekervlotbrug, Koedijk, Alkmaar
• 
  Vlotbrug, Sint Maartensvlotbrug, Schagen
• 
  Vlotbrug, 't Zand, Schagen

Elsewhere

• 
  Vlotbrug,Hellevoetsluis,South Holland
• 
  Vlotbrug,Merwedekanaal,South Holland (c. 1970)
• 
  De Scholle, Vroomshoop, Overijssel

See also

• Moveable bridge

Further reading

• de Jong, Henk; Muyen, Nico (2001).Bruggen in Nederland(in Dutch). Atrium Holding BV.ISBN9789061139324.
• "Bedrijvenvereniging Zuid-Zijpe".bedrijvenverenigingzuidzijpe.nl(in Dutch).Retrieved10 November2017.A collection of news items about vlotbruggen.

External links

• KoedijkervlotbrugonYouTube.An amateur video of Koedijkervlotbrug opening to allow a ship to pass through and then closing again.
• Vlotbrug 't Zand jni 2014onYouTube.An amateur video of 't Zand vlotbrug opening to allow a ship to pass through and then closing again.