The Vikings were not the first people to build ships but they did build the best ships anyone had made up to that time. Viking ships often had Dragons heads mounted on the bow to scare off sea monsters.
doesn't really look like a dragon to me. It is a terrifying image though so I can see why the Vikings included images of dragons on the front of their ships. It was a way to intimidate their opponents.
Viking longboat ships were used to travel from one raid to another. The act of pillaging and conquering other lands has often left a negative stigma on the Vikings, but amongst the Gods of Norse Mythology;