The Swedish battlefleet had spent the winter at Karlskrona which was struck by relapsing fever epidemic during the stay. Epidemic had started from the capture of the Russian ships of line "Vladislav" during the Battle of Hogland in 1788. From the captured sailors the disease had spread widely into the fleet during its prolonged stay at Sveaborg in 1788 was carried with the fleet to Karlskrona later that year. Fitting ships for the sealing season proceeded very slowly and was greatly hindered by the losses suffered due to the illness to the crews. From December 1788 to September 1789 total of 26,249 were treated for sickness in naval hospitals at Karlskrona alone of whom 5,286 perished while the total death toll of the epidemics is assumed to be around 15,000 lives. By the end of June thousands of soldiers had to be sent from the infantry as reinforcements for the fleet. Regardless of the obstacles Admiral Otto Henrik Nordenskiöld who was responsible for refitting was able to ready fleet of 21 ships of the line and 8 frigates for sailing already for 6 June however without crews.