The goal for the Dano-Norwegian forces was to achieve a quick end of the war with a resulting territorial loss for Sweden, but also to halt the Swedes' privateering operations which were taking a toll on Denmark–Norway.

During the battles in and around Marstrand, large parts of the Gothenburg Squadron were sunk by friendly forces in order to prevent its vessels from falling under enemy control.

Just before hostilities would calm down in the autumn of 1719, Tordenskjold launched yet another assault on Nya Varvet, this time with fewer troops but ultimately resulting in a more successful operation than the one that preceded it.

Subsequent Russian attacks resulted in the seizure of Swedish defense structures across all of the Baltic region as well as parts of Finland.

This situation was a major strain on Swedish resources and it made the defense of their western waters from the Dano-Norwegian fleet especially difficult.

In 1704 it was decided that forced naval conscription was to be performed in the former Danish provinces (Scania, Bohuslän and Halland, among others) which were now part of southern Sweden.

This meant that the part of the population that were fit for naval service were obliged to serve the navy during times of war, in exchange for some benefits.

By 1715, a total of 25 Swedish privateers were conducting active operations in the Western Sea, which disrupted Dano-Norwegian trading routes severely.

Repeated attempts to defeat the Norwegian forces around Swedish-occupied Christiania failed because of General von Lützow's skilled defensive tactics and by him avoiding as many battles as possible, since he was aware that his relatively untrained army couldn't compare to the seasoned Swedish Caroleans.

The rough Norwegian terrain, combined with the lack of supplies and the active resistance of the local civilians forced the Swedish army to retreat south.

The commander of the Gothenburg Squadron, Vice admiral Axel Lewenhaupt, had only managed to put one frigate, the Älvsborg (46 cannons) to sea, by letting privateers borrow it for 20 000 daler.

[10] In Gothenburg, Vice-Admiral Lewenhaupt had under rough circumstances managed to put together a transport fleet consisting of 24 vessels loaded with siege cannons, ammunition and other supplies.

[11] During the night of June 28, Norwegian Commander Peder Tordenskjold initiated one of the most daring and most widely renowned naval battles in Nordic history.

[12] By sailing directly into the approximately 5 kilometer long and narrow fjord with frigates, galleys and armed barges, the Swedes were taken by surprise.

The Dano-Norwegian superior number of cannons meant that the entire Swedish transport fleet was either sunk or captured after five hours of combat.

[13] Without any usable siege artillery, and with a high risk of being cut off, Charles XII ordered a full retreat of the Swedish army on June 29.

The Swedish captain Strömstierna managed to reach land from the galley Wrede, and despite his defeat, he was promoted to vice admiral by Charles XII.

In the morning of May 2, 1717, a Dano-Norwegian naval force anchored in the Gothenburg archipelago with the purpose of conducting a night raid against Swedish harbors and dockyards in the city, but their moment of surprise was lost from the beginning.

[16] The Danes under the command of Tordenskjold, still managed to maneuver past Nya Älvsborg fortress with barges, galleys and slopes containing around 100 cannons and 1800 soldiers, during the night between 2 and 3 May.

[23] On July 8, Tordenskjold assaulted Strömstad with a squadron, and following heavy firing upon the city, an attempt was made to land soldiers escorted by galleys.

Due to the fact that the entrance to Svinesund was blockaded by naval vessels and Norwegian cannon batteries, Charles XII decided that a number of galleys should be towed across land from Strömstad to Trångsviken in the Ide fjord, a distance of roughly 20 kilometers.

[27] The roughly 40 tonne ship got stuck in a trickle and remained immobile until technical experts Christopher Polhem and Emanuel Swedenborg were called upon to remove the vessel.

On September 10, under the command of Charles XII, the Swedish vessels, including brigantines and sloops, forced the Norwegian squadron to retreat to Fredrikshald during a battle in the Ide fjord.

[28] Following the renewed campaign against Norway in the autumn of 1718, and the subsequent death of Charles XII at Fredriksten fortress on November 30, the Swedish army marched back across the border into Sweden.

[31] In early June, the blockading naval force had increased to seven ships of the line, two frigates, four barges, two floating batteries, one bombarderskip, five galleys and two galiots.

On May 23, Field Marshal Carl Gustaf Rehnskiöld was appointed commander of the Swedish troops in Bohuslän, and in early June, an inspection was started in the region.

[33] Due to the strong Danish blockading force outside of Gothenburg, with an estimated manpower of 1300 soldiers on board and with several special purpose vessels able to bombard coastal defense positions, it was predicted that the Danes were planning an attack on either Marstrand or Älvsborg fortress.

Georg Bogislaus Staël von Holstein and his soldiers from the Skaraborg Regiment had a good visual over the Danish batteries in Aspholmarna, but could not reach them with his musketeers.

In the early hours of September 1, a Swedish force based in Nya Varvet ("the New Yard") managed to overtake and capture a number of Danish vessels near Grötö.

Meanwhile, Tordenskjold himself arrived in a slope to Nya Varvet, but then the alarm had been raised because of a few guards escaping capture, and reporting the events to Major Ernbildt.