If you read the Politikos you will see that the most frequent analogy to explain the ruler who possesses the gnostic faculty is that of the pilot of a ship. The ship is the city, the pilot the ruler - the perfect ruler is understood to rule not with laws but with the gnostic faculty that connects with the supernal power that helped establish the laws.
The term naukleros also figures in the writings of Plato. He is not the pilot but the master of the pilot.
The term episcopos also figures in the writings of Plato. The term is applied to Dike (Justice) to imply that Dike watch over the world as that supernal power.
The Catholic use of the term episcopos isn't overtly Platonic but the Marcionite use of the term is. Marcion is the source (episcopos) of the various Marcionite church leaders according to Megethius. My guess is that the Marcionite Church had one bishop - Mark/Marcion - and many officials called by a different name. As an interesting parallel the Alexandrian Church had only one bishop until Demetrius (or 189 CE). I think the two traditions are related because Marcion = St Mark.
So if the various Marcionite church officials weren't called 'bishops' (episcopoi) what was their title? I think it was gnostokoi based on Clement of Alexandria's use of the term and the parallels with Alexandrian tradition and Marcionitism (i.e. Mark is the source of all the Alexandrian Popes etc.).
If the Markan tradition identified its bishops gnostikoi then naukleros as an epithet of Marcion makes sense because a naukleros was a figure in command of a number of piloted ships.
The alternative is that they were called kubernetes a term which eventually forms into a word meaning 'governor' (our English word is directly related to the Greek). The implication is still the same - the reason that the Church Fathers are ridiculing the apparent ritual identification of Marcion as a naukleros is because the Marcionite church as a whole was developed very closely from the original Platonic ideas still evident in Alexandrian Christianity. The Church as a whole looked like a fleet of belonging to a shipmaster
Stephan Huller has had a life long interest in religion and spirituality 
dating back to conversations with his grandfather, Gaston Frank. "He said we represent one of the last descendants of the Frankist Jewish faith in the world," he muses. "I grew up thinking that our family was something like the Last of the Mohicans."