Thalamegos (Ancient Greek: θαλαμηγός = "room carrier" from the Greek Thalamos (room) + Ago (haul/carry/lead) was a 115 by 14 m (377 by 46 ft), 20 m (66 ft) high, two-story Nile river palace barge. The huge twin-hulled catamaran was commissioned by Hellenistic king Ptolemy IV Philopator for himself and his wife Arsinoe III ca. 200 BCE.
- Casson, Lionel (1986). "Chapter Fourteen: Small Craft". Ships and Seamanship in the Ancient World. New Jersey: Princeton University Press. pp. 341–342. ISBN 0-691-00215-0. Retrieved 29 April 2022.
- Casson, Lionel (1995). "Chapter 14: Small Craft". Ships and Seamanship in the Ancient World. Baltimore: The Johns Hopkins University Press. pp. 341–342. ISBN 0-8018-5130-0. Retrieved 17 June 2010.