 Their build was not designed for battle at sea, as this was a form of warfare that the Vikings very rarely engaged in, but these long narrow ships could accommodate 50–60 seamen who powered the ship by rowing, as well as a complement of warriors, and so able to carry sizeable forces at speed to land wherever advantageous.Due to their shallow draft, Viking ships could land directly on sandy beaches rather than docking in well-fortified harbours.Viking ships made it possible to land practically anywhere on a coast and to navigate rivers in Britain and on the Continent, with raids reported far up rivers such as the Elbe, the Weser, the Rhine, the Seine and the Loire, the Thames, and many more.