Drawing of the Battle of Jasmund 1715 by an unknown artist. Public domain via Wikimedia Commons. Attributed to the collection of the Marin Museum at Karlskrona, Sweden, but the Wikipedia link to the item is broken.
Military Action Between Sweden and Denmark in 1715
My main source is the excellent collection in two hardcover volumes, the “Great Northern War Compendium,” edited by Steven Kling, cited below. It is available for sale on Amazon.
The year 1715 saw naval action between Sweden and Denmark off the northern coast of Germany in Fehmarn, Rügen and Jasmund. Rügen is an island off the northern coast of Germany near Jasmund, actually in the Duchies of Schleswig and Holstein in 1715. The duchies had shared rule between German dukes and the Danish king, but had come under the control of Sweden during the Great Northern War.
The Siege of Stralsund
The German fleet was moving supplies to their fortress in Stralsund. Charles XII himself was present during the siege that lasted from July to December of 1715, when the Swedes lost control of Stralsund to an allied force of the Prussian, Saxon, and Danish armies. The extreme cold of the late fall meant the moat froze and the large allied force easily captured the outer works of the fortress. Charles XII escaped on a Swedish brig named Snappup before the end the of the siege (Boll 204-2055).
Naval Action off Fehrman and Rügen
The Swedes were defeated at sea by the Danish navy twice in 1715, at Fehrman and again at Rügen.
In April 1715, a fleet of six ships under the command of Swedish Rear Admiral Carl Hans Wachtmeister raided the Danish coast near Fehrman. A larger Danish force of twelve ships under the command of Danish Admiral Christian Carl Gabel caught up with them and after a few hours ran the Swedish fleet aground. All but the flagship Prinsessa Hedvig Sophia were captured (Kling 249-250).
In the action off the Island of Rügen in July 1715, the Swedish and Danish fleets lined up and fired broadside at each other, but were turned back by foul weather. The action lasted from 2pm to 8pm. The Danes captured one Swedish ship (Kling 250). Rügen lay off the coast at Jasmund, so the art depicted above is likely of the action at Rügen.
SOURCES:
Kling, Steve. “Naval Operations During the Great Northern War,” in Great Northern War Compendium, volume 2, edited by Steve Kling (St. Louis: THGC Publishing, 2015), pp. 243-252.
Boll, Jens Kristian. “Is God Not on My Side Anymore?” in Great Northern War Compendium, volume 2, edited by Steve Kling (St. Louis: THGC Publishing, 2015), pp. 199-206.