The Long Forties and the Broad Fourteens are large areas with roughly uniform depth in fathoms, (forty fathoms and fourteen fathoms or 73 and 26 m deep respectively).
These great banks and others make the North Sea particularly hazardous to navigate, The Devil's Hole lies 200 miles (320 km) east of Dundee, Scotland.
In the North Sea there are two amphidromic systems and a third incomplete amphidromic system.
An epeiric (or "shelf") sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north.Some of the energy from this wave travels through the English Channel into the North Sea.The wave still travels northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the Kelvin wave turns east and south and once again enters into the North Sea.It was only around the beginning of the High Middle Ages, in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground.The North Sea Floods of 19 were impetus for further raising of the dikes as well as the shortening of the coast line so as to present as little surface area as possible to the punishment of the sea and the storms.It was also important globally through the power northern Europeans projected worldwide during much of the Middle Ages and into the modern era. Subsequently, the Hanseatic League, the Netherlands, and the British each sought to dominate the North Sea and thus the access to the markets and resources of the world.