Lashed-lug boat

Lashed-lug boats are ancient boat-building techniques of the Austronesian peoples. It is characterized by the use of raised lugs (also called "cleats") on the inner face of hull planks. These lugs have holes drilled in them so that other hull components such as ribs, thwarts or other structural components can be tied to them with natural fiber ropes (hence "lashed"). This allows a structure to be put together without any metal fastenings. The planks are further stitched together edge-to-edge by sewing or using dowels unto a dugout keel and the solid carved wood pieces that form the caps for the prow and stern. Characteristically, the shell of the boat is created first, prior to being lashed unto ribs. The seams between planks are also sealed with absorbent tapa bark and fiber that expands when wet or caulked with resin-based preparations.

This shipbuilding tradition is considered to be an example of parallel evolution, as it is found in Scandinavian boats covering a period from 400 BCE to the 9th century AD. There, the term "cleat" is applied to the blocks carved out of the hull planks, and essentially the same role is performed as with the "lugs" in lashed lug construction. In the Scandinavian archaeological examples, planks may be sewn together, held with iron fastenings or with treenails. The two regional uses of this method are considered cases of independent invention of one of a limited number of solutions to the same boat-building problem.

Lashed-lug construction has been used on a wide size range of vessels, from small craft, such as logboats that have had planks added to their sides to increase their freeboard, to large plank-built ships. It is found in traditional boats of Maritime Southeast Asia, Melanesia, Madagascar, Micronesia, and Polynesia. It forms part of the maritime technology associated with Austronesian peoples in their spread throughout the islands of the Indo-Pacific. The oldest recovered remains of ships of lashed-lug construction is the Pontian boat of Malaysia dated to at around c.260–430 CE.