Additionally about 500 Cossacks under Konstanty Kołek with their small boats (Chaika) were brought. It is uncertain if they were used at all. Their main goal was to plague Swedish communication and supply lines near Piława and on Zatoka Wiślana (Vistula Bay). There were plans to use Cossacks in their light but very fast boats against Inflanty (Livonia) and even to raid the Swedish shore (to burn, pillage, capture merchant ships etc.). Cossacks were known from their plundering raids on Black Sea (they even burned suburbs of Istanbul once or twice). Because of the overall tonnage and armament difference between Polish and Swedish naval fleets even before (in 1620s), the main role of the Polish fleet was to disrupt Swedish communication and supply lines, to capture merchant ships bringing supplies for the Swedes.