He was one of the first Greek officers to study hydrography, a largely ignored subject (considered as "irrelevant" by most), for which he was derisively nicknamed "the teacher".
His obsession with the subject, taking regular depth and sea temperature measurements, resulted in his dismissal "for abandoning his position" in the same year.
As captain of the ship Methoni, he further enhanced his knowledge on the subject by onberving the measurements made by the British hydrographer Arthur Mansell in the Euripus Strait.
Miaoulis was the first Greek hydrographer, and discovered the namesake reef in the Ionian Sea.
He published papers concerning the tidal currents in the Euripus Strait, as well as those predicted for the new canal at the Isthmus of Corinth.