Laudator Temporis Acti

Appian, Roman History 5.10.96 (tr. Horace White):

When the fleet was ready, Octavian performed a lustration for it in the following manner. The altars are erected on the margin of the sea, and the multitude ranged around them in a circle of ships, observing the most profound silence. The priests who perform the ceremony offer the sacrifice while standing at the water's edge, and carry the expiatory offerings in skiffs three times round the fleet, the generals sailing with them, beseeching the gods to turn the bad omens against the victims instead of the fleet. Then, dividing the entrails, they cast a part of them into the sea, and put the remainder on the altars and burn them, while the multitude chant in unison. In this way the Romans perform lustrations of the fleet.

ἐπεὶ δ' ἕτοιμος ἦν ὁ στόλος, ἐκάθαιρεν αὐτὸν ὁ Καῖσαρ ὧδε. οἱ μὲν βωμοὶ ψαύουσι τῆς θαλάσσης, καὶ ἡ πληθὺς αὐτοὺς περιέστηκε κατὰ ναῦν μετὰ σιωπῆς βαθυτάτης· οἱ δὲ ἱερουργοὶ θύουσι μὲν ἑστῶτες ἐπὶ τῇ θαλάσσῃ καὶ τρὶς ἐπὶ σκαφῶν περιφέρουσιν ἀνὰ τὸν στόλον τὰ καθάρσια, συμπεριπλεόντων αὐτοῖς τῶν στρατηγῶν καὶ ἐπαρωμένων ἐς τάδε τὰ καθάρσια, ἀντὶ τοῦ στόλου, τὰ ἀπαίσια τραπῆναι. νείμαντες δὲ αὐτά, μέρος ἐς τὴν θάλασσαν ἀπορρίπτουσι καὶ μέρος ἐς τοὺς βωμοὺς ἐπιθέντες ἅπτουσι, καὶ ὁ λεὼς ἐπευφημεῖ. οὕτω μὲν Ῥωμαῖοι τὰ ναυτικὰ καθαίρουσιν.

See H.S. Versnel, Inconsistencies in Greek and Roman Religion, Vol. II: Transition and Reversal in Myth and Ritual (Leiden: E.J. Brill, 1993), pp. 300-301.