I’m reading this book about the Temple of Aset at Syene/Aswan and I found this festival to Wesir listed.
28 of Tybi
Procession of Wesir/Osiris to the Land of Nubia, bringing things of the Greeks
From the texts it seems that a boat was used in the procession.
Dijkstra, Jitse H. F. and Eugene Cruz-Uribe. Syene I: the figural and textual graffiti from the temple of Isis at Aswan. (Phillip von Zabern, 2012), 147.