опытный в мореплавании

From LSJ

κρῖναι δὲ λόγῳ πολύδηριν ἔλεγχον ἐξ ἐμέθεν ῥηθέντα → judge by reason the too much contested argument which has been given by me

Source

Russian > Greek

θαλάσσιος, θαλάττιος, θαλασσίδιος