Since 1868, pilotage services have been provided in Puumalansalmi Strait, which is an important node in the network of ship routes between the southern and northern part of Saimaa. Ships also use the Saimaa deep-water channel, and if you are at the right place at the right time, you may see a changing of pilots while the ship is underway. Pilots board the ship from a boat that draws up alongside it. Vessels sailing under a foreign flag are not allowed to navigate the labyrinthine Saimaa waters without a pilot. In the dark of autumn and winter the job is demanding, with 400−600 pilot changes made each year. Most of the ships are Russian and Dutch. You can monitor ship traffic on Saimaa online at https://www.finnpilot.fi/ais
