What characteristics would the viking boat need to have?

A Viking boat, or longship, needed to be long and narrow for speed and agility, allowing it to navigate both open seas and shallow rivers. It required a shallow draft to enable beach landings and river travel, while its clinker-built construction (overlapping planks) provided flexibility and strength. Additionally, a single square sail and multiple oars offered versatility in various wind conditions, making these vessels effective for raiding and exploration. Lastly, a dragon or serpent figurehead was often added for intimidation and to ward off evil spirits.