Many Vikings were good sailors because they lived close to rivers and fjords (sea inlets). They grew up learning how to use ships for fishing and travelling.
The Vikings built fast ships for raiding and war. In a raid, a ship could be hauled up on a beach and the men would jump out to fight. They could make a quick getaway if they were chased.
A big Viking longship would be about 30 metres long and could carry 60 men. The men slept and ate on deck. When rowing, sailors sat on chests with their belongings in.
They were made from planks of oak wood joined together. These overlapped each other, which made the ship very strong.
A Viking ship had a large, square sail made of woven wool. It was brightly coloured in stripes or diamond patterns. In bad weather, they would be lowered over the ship and fastened down like a tent to protect the men inside. The ships could sail at about 10mph.
The ship was steered using a rudder, at the back of the ship. When there was no wind, oars were used to row the ship. They covered the oar holes to stop the sea splashing in when using the sail.
The Vikings loved to decorate their ships with fine wooden carvings. The head of a fearsome creature like a snake or dragon was put at the front to scare off enemies, including supposed sea monsters.
To find their way, Vikings usually sailed close to the coast, watching for land marks. At night, they used the stars to help them navigate in the right direction.
You can see two Viking longships in a museum in Oslo, in Norway. They were found by archaeologists (people who dig up the ground to look for old objects).
The Vikings gave their ships names like: Long Serpent, Raven of the Wind or Snake of the Sea.