This Viking ship, on display at the Viking Museum in Oslo, Norway, is an example of lapstrake construction. In Viking ships of the 9th century and later, external planks were overlapped and lashed to the ships frame, producing a strong, flexible hull.
In northern Europe, Scandinavian shipbuilders had been practicing a unique construction technique since the 4th century BC. They constructed a vessel by laying a wooden backbone, or a keel, then attaching successive overlapping strakes (planks) until a hull was formed. After finishing the hull, the Scandinavians inserted a skeletal framework to strengthen and support the vessel. This building method, called lapstrake, is unique in that each run of planking overlaps the one below it. Shipwrights used iron fasteners, or clinch bolts, to hold the double thickness of planking together. From the word clinch, this form of building also became known as clinker building.
By the 8th century AD, Nordic peoples called Vikings regularly traveled in clinker-built vessels designed for trade, transport, and warfare. Viking longships with 80 oars or more and a single removable mast with a square sail carried warriors into battle. The sailors lowered and stored the mast when traveling under oar power. Longships had a shallow draft, a design that enabled Vikings to navigate rivers and streams. This design permitted them to take many inland settlements by surprise because the inhabitants did not expect an attack from the water.
National Geographic The Vikings Ships Documentary
Viking ships, because of their shallow draft, were able to successfully navigate rivers and streams that many other vessels could not. This allowed the Vikings to raid settlements far upriver from the sea, settlements that frequently were not prepared for an attack from the water.
The Viking ship had no deck and offered its crew little protection from the wind and water. Nonetheless, the Vikings traveled great distances in their ships. They traded and raided along the northern seas, founded Dublin in Ireland, conquered much of England, invaded France, and descended the rivers of eastern Europe as far as Kiev and Constantinople. Norse Vikings led by Leif Ericson sailed west to Greenland, Iceland, and Vinland (probably present-day Newfoundland and Labrador) in North America.
Historians know a good deal about these ships because the Vikings, like the ancient Egyptians, sometimes buried important members of their communities with ships. In 1904 archaeologists found the remains of an early 9th-century ship while excavating a Viking burial mound located on a farm near Oslo, Norway. The ship, which has come to be known as the Oseberg ship for the farm on which it was found, has a 22-m (71-ft) clinker-built hull with an elegantly curved bow and stern. It had a single mast and accommodated 30 oars. The ancient shipwright had used baleen, or whalebone lashings, to fix wooden supports to the hull.
The similarly constructed Gokstad ship was discovered in a burial mound in Norway in 1880. Built about 850, this ship had a single mast that supported a square sail. It was 24 m (78 ft) long, with a breadth, or beam, of about 5 m (17 ft), and it was steered with a steering oar controlled by a wood bar called a tiller. In 1893 enthusiasts built a replica of the Gokstad ship and sailed it from Bergen, Norway, to New York, New York. Similar replicas have crossed the Atlantic Ocean several times.