Clinker built (also known as lapstrake) is a method of boat building where the edges of hull planks overlap each other. Where necessary in larger craft, shorter planks can be joined end to end, creating a longer strake or hull plank. The technique originated in Scandinavia, and was successfully used by the Anglo-Saxons, Frisians, Scandinavians, typically in the vessels known as cogs employed by the Hanseatic League. Carvel construction, where plank edges are butted smoothly, seam to seam, supplanted clinker construction in large vessels as the demand for capacity surpassed the limits of clinker construction. (See Comparison between clinker and carvel below.). Examples of clinker-built boats that are directly descended from those of the early medieval period are seen in the traditional round-bottomed Thames skiffs, and the larger (originally) cargo-carrying Norfolk wherries of England. Etymology From clinch, or clench, a common Germanic word, meaning “to fasten together”. Origin The technique of clinker developed in the Nordic shipbuilding tradition as distinct from the Mediterranean mortise and tenon planking technique which was introduced to the provinces of the north in the wake of Roman expansion. Overlapping seems to already appear in the 4th century BC Hjortspring boat. The oldest evidence for a clinker-built vessel, dendrochronologically dated to 190 AD, are boat fragments which were found in recent excavations at the site of the Nydam Boat. The Nydam Boat itself, built ca. 320 AD, is the oldest preserved clinker-built boat. Clinker-built ships were a trademark of Nordic navigation throughout the Middle Ages, particularly of the longships of the Viking raiders and the trading cogs of the Hanseatic League. Planking In building a simple pulling boat, the keel, hog, stem, apron, deadwoods, sternpost and perhaps transom are assembled and securely set up. In normal practice, this will be the same way up as they will be in use. From the hog, the garboard, bottom, bilge, topside and sheer strakes are planked up, held together along their ‘lands’ – the areas of overlap between neighbouring strakes – by copper rivets. At the stem and, in a double-ended boat, the sternpost, geralds are formed. That is, in each case, the land of the lower strake is tapered to a feather edge at the end of the strake where it meets the stem or stern-post. This allows the end of the strake to be screwed to the apron with the outside of the planking mutually flush at