The Dogger Bank, a vast moraine, or accumulation of unconsolidated glacial debris, rises to a mere below the surface. This feature has produced the finest fishing location of the North Sea. The Long Forties and the Broad Fourteens are large areas with roughly uniform depth in fathoms, (forty fathoms and fourteen fathoms or deep respectively). These great banks and others make the North Sea particularly hazardous to navigate, which has been alleviated by the implementation of satellite navigation systems. The Devil's Hole lies east of Dundee, Scotland. The feature is a series of asymmetrical trenches between long, wide and up to deep.