This paper examines an undernoticed theme of the papyrus archive of the Theban royal bank, contextualizing data on Amun’s Userhat boat and the Theban religious festivals in the later Ptolemaic period. The bank archive reveals the fraudulent use of money deposits destined for the replacement of two iron anchors for the Userhat and for the maintenance of this sacred riverine ship which transported Amun’s sacred bark twice a year (during the Opet and the Valley Festivals). The Userhat is well attested in the pharaonic period, while the information for the Ptolemaic era, though scarce, shows that the main Theban festivals were still organized and that the Userhat still played a major role. The documentary evidence offers more detail on royal investment in the ship’s maintenance even during a civil war, its outer appearance, on the saline basin where it was moored and the storage place of its removable parts. The association of the Ptolemaic Userhat with the Opet temple, as suggested by the bank records, fits with a shift in focus towards this sanctuary in the later Ptolemaic period.