ploviti

1. (of a ship, people) to sail; to navigate
   Brod plovi Dunavom prema Beogradu. — The ship is sailing along the Danube towards Belgrade.
   Leti volimo da plovimo duž obale. — In summer we like to sail along the coast.
2. (of objects, clouds) to float; to drift
   Oblaci polako plove nebom. — Clouds are slowly drifting across the sky.

The route is usually in the instrumental without a preposition: ploviti morem, rekom. Occasionally used figuratively of the internet (ploviti internetom), but the normal verb is surfovati.