The Tessarakonteres was a massive, impractical catamaran built for show by an Egyptian king

Countries & Cities · Published 15 October 2026 Swipe more like this →

In short: In the 3rd century BC, Ptolemy IV Philopator constructed a gargantuan galley known as the forty. With thousands of rowers and a deck large enough to host an army, this vessel was likely the largest human-powered ship of antiquity, though historians debate whether it was ever truly seaworthy.

The Tessarakonteres, or forty, was a prestige vessel commissioned by Ptolemy IV Philopator of Egypt. Ancient writers like Callixenus of Rhodes and Athenaeus described a ship of immense proportions, measuring 280 cubits in length. Its name did not signify forty horizontal ranks of oars—a physical impossibility—but rather the number of rowers assigned to each vertical section of the ship. Modern research by Lionel Casson suggests the vessel was likely a catamaran, formed by joining two three-ranked hulls with a massive deck, allowing it to accommodate its reported crew of 4,000 rowers and nearly 3,000 marines.

The engineering required to launch such a craft was equally ambitious. A Phoenician engineer reportedly devised a dry dock system, excavating a trench and using stone props and cross-beams to support the ship. By channeling seawater into the trench, the vessel could be floated and then secured as the water was drained away using mechanical pumps. Estimates suggest this process required approximately 750,000 gallons of water. Despite these technical feats, the ship was widely regarded as a stationary exhibition piece rather than a functional warship, as its size made it difficult to maneuver and potentially dangerous to operate at sea.

Skeptics have long questioned the accuracy of these ancient accounts. Critics like Frank Boott Goodrich have pointed to the logistical impossibility of managing 4,000 rowers and the structural strain a catamaran of that scale would face in open water. Furthermore, the oars required for the top tier would have needed to be roughly 70 feet long, a feat of timber engineering that remains highly improbable for the era. Whether the Tessarakonteres was a literal triumph of Hellenistic naval architecture or a product of exaggerated royal propaganda remains a subject of historical debate.

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