The history of Karlskrona and Vämövarvet is closely related to the fleet's disastrous efforts during the Scanian War 1675-79. While the Swedish fleet sat frozen in the ice near Stockholm, the Danish fleet was able to set out early and control and dominate the waters around the countries.
It was necessary to establish a naval base considerably further south, so that the ice would arrive later and disappear sooner. An early attempt had been made in Karlshamn where a crown yard was built. However, this turned out to be too close to the border and was captured by the Danes in 1676. After reconnoitering the Blekinge coast, they got stuck on what would later become Karlskrona.
In 1679, Charles XI decides that the coming winter storage (1679-1680) of the ships will be in Blekinge. Timber was procured so that boatmen's quarters could be built in Lyckeby. The fleet was stationed at Hästö.
The location in the eastern part of Blekinge, with the protective islands around, was as close to perfect as possible,
If you drive up Bryggareberget, you will see how right they were. Senoren, Sturkö, Tjurkö, Aspö and Hasslö lie in a semi-circle around Trossö and the inner islands, and were excellent protection and good places to build fortifications.