3. Naval Architecture. The Hellenistic Hull Design

During the Hellenistic period and the Roman Republic, there was a dominant architectural design in Mediterranean naval architecture, which was eventually adopted by Greek and Roman shipyards as well as Punic. This system is characterised by a tripartite structure (keel, planking, framing). It allows the building of large ships with an elaborate hull shape, capable of good nautical performance, and this was clearly one of the factors behind the significant maritime expansion at the end of the first millennium BC. Of course, many other architectural approaches continued to be used in shipbuilding, which were testament to regional and local traditions.

The origin of this architectural system lies in the Greco-Roman evolution — between the second half of the sixth and the end of the fourth century BC — of sewn boats in the Greek tradition (influenced by the Phoenicians), which introduced the method of assembly by mortise and tenon. This resulted, throughout the Mediterranean, in a convergence of Greek and Phoenico-Punic architectural systems. However, during the Roman Empire, this approach — which presents a structural weakness at the level of the keel — was replaced by a new architectural type, apparently more robust, characterized by a flat bottom section, overlapping frames, and a keelson/mast step timber fitted on lateral sister-keelson.