The construction of a longship was a colossal undertaking that required tens of thousands of hours of labor to complete when you count all of the various components of the process together. Those components included cutting the wood and transporting it to the building site, building the main body of the ship, forging the nails and other iron elements, fastening them in place, burning the tar, making the ropes, and weaving and sewing the sail. A great number of both men and women had to be working toward this common goal to bring it to fruition.
Shipbuilding required a huge amount of top-quality timber. Wood wasn’t only used for the planks of the main body of the ship; it was also used for “treenails and wedges, oars, rudders, rigging blocks, gangplanks and bailers; for clamps, battens, stakes, shores and the stocks on which the vessels were built; and for skids and launching ways.”
Oak, which grows in the south of Scandinavia, was the most highly-prized wood for building ships, due to its exceptional strength and flexibility. In fact, in Viking poetry, the word “oak” was frequently used as a metaphor for “ship.” When oak wasn’t available, pine, maple, or birch were made to suffice.
The planks of Viking-Age ships weren’t sawed, but were instead cut along the natural grain of the wood with axes and wedges. This made them more flexible and easier to bend. They were then arranged to form the hull of the ship by means of the “clinker” or “lap-strake” method, which involved placing the planks with a slight overlap with each other – producing an effect that visually resembles steps – then fastening the planks together with nails, and then installing frames and ribs to ensure that the ship would hold its shape.
Wool was the most common material used for caulking between the planks to seal any gaps, and the whole hull was then covered with a coating of pine tar to make it waterproof.
Viking ships that participated in any significant degree of fighting and traveling (rather than just being trophies displayed by their owners) required constant repairs, and had a lifespan of a few decades at most before they were no longer seaworthy and had to be replaced. They were much like our cars in this regard.