In Norway’s western region, the towns of Kristiansand in the south and Trondheim in the north are connected by Highway E39, a 683.5-mile highway that takes 21 hours to traverse because it crosses seven major fjords, as well as several other smaller fjords, channels, and inlets that can only be crossed by ferries or helicopter. So, City Metric reports, Norway is looking at constructing underwater bridges, known as submerged floating tunnels (SFT), that will sit 30 to 100 feet under water, with vertical tethers attached to the seabed or to floating pontoons on the surface of the water.
If SFTs were to be built along the E39 route, travel times could be cut in half.
The idea may seem far-fetched, but according to the report, in 1865, Sir Edward James Reed, a naval architect and author who served as Chief Constructor of the British Royal Navy from 1863 to 1870, suggested the idea of underwater bridges in Parliament as a means of crossing the English Channel. Although the idea didn’t get much attention at the time, today it might actually be feasible.
Arianna Minoretti from the Norwegian Public Road Administration (NPRA) which is managing the project, tells the news agency that she likes the SFT option—or “hidden” bridge, as she calls it—because the technology and resources to construct such a tunnel are now feasible.
The report notes that a paper published in 2007 by a Norwegian academic and a group of engineering consultants looked into the possibility that these types of tunnels could be “extended perhaps by a factor of 100 or more” into “Very Long Tunnels” (VLT) “to serve the developments in long distance travel in Maglev,” the super-fast train that floats above the tracks using magnetic levitation (Maglev). They could also possibly be the answer for a Trans-Ocean Tunnel (TOT) connecting countries on either side of the Atlantic Ocean.