It seems that the εὐθύνειν "keep it on course / on a straight line" is just one of the functions of a κυβερνήτης "pilot". Am I right in thinking that using ὁ εὐθύνων seems to drawing attention to a particular function that the κυβερνήτης carries out. OR Is a κυβερνήτης only used of the person directing a larger vessel, cf.James 3:4 wrote:Ἰδού, καὶ τὰ πλοῖα, τηλικαῦτα ὄντα, καὶ ὑπὸ σκληρῶν ἀνέμων ἐλαυνόμενα, μετάγεται ὑπὸ ἐλαχίστου πηδαλίου, ὅπου ἂν ἡ ὁρμὴ τοῦ εὐθύνοντος βούληται.
Acts 27:11, 41 wrote:Ὁ δὲ ἑκατοντάρχης τῷ κυβερνήτῃ καὶ τῷ ναυκλήρῳ ἐπείθετο μᾶλλον ἢ τοῖς ὑπὸ τοῦ Παύλου λεγομένοις.
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Περιπεσόντες δὲ εἰς τόπον διθάλασσον ἐπώκειλαν τὴν ναῦν· καὶ ἡ μὲν πρώρα πρῷρα ἐρείσασα ἔμεινεν ἀσάλευτος, ἡ δὲ πρύμνα ἐλύετο ὑπὸ τῆς βίας τῶν κυμάτων.
NB.Revelations 18:17 wrote:ὅτι μιᾷ ὥρᾳ ἠρημώθη ὁ τοσοῦτος πλοῦτος. Καὶ πᾶς κυβερνήτης, καὶ πᾶς ὁ ἐπὶ τόπον πλέων, καὶ ναῦται, καὶ ὅσοι τὴν θάλασσαν ἐργάζονται, ἀπὸ μακρόθεν ἔστησαν,
The πηδάλιον "rudder" is the part in the water, while ὁ οἴαξ (-ακος, also οἰάκιον) "tiller" is the part in his hand.