Gustav Vasa was determined to build up his navy as well as his army, and he sought foreign assistance not only to man his ships but also to design and build them; Scotland was one of the places he looked to for this help. By the time the king died in 1560 he had some nineteen warships in his fleet. Erik XIV continued this naval development, with the principal aim of confronting the power of Denmark, and indeed the Swedish navy, under the command of the sea-going general Klas Horn, defeated the Danes as well as the Lübeckers in 1565–66. Frederick II of Denmark wrote to Mary, Queen of Scots, in April 1566 to protest about a ship being made ready in Leith to join the Swedish fleet. Among the Swedish ships in 1566 was one called Skotska Pinckan, taken from the Danes but recaptured again; the name suggests a Scottish origin. Another, in the early 1600s, was bought from Scotland and bore the name Skotska Lejonen – Scottish Lion. Karl IX established the main naval base at Karlskrona in order to benefit for as much of the year as possible from ice-free water.
Despite these developments, by the time Gustavus Adolphus came to the throne the Swedish ships were still outgunned by the Danes. The ability to project military might overseas was essential to Gustavus Adolphus’s foreign policy in the Baltic; as navies have always done, his had to convey troops safely to foreign shores, maintain supply lines, defend trade and also impress outsiders as symbols of prestige and authority. A new threat to Sweden appeared in the late 1620s when, by the capture of north German ports, Wallenstein created the spectre of a Habsburg navy afloat in the Baltic. It was a threat real enough to persuade Gustavus Adolphus and Christian IV to overlook their rivalry and cooperate to keep Stralsund from the Imperial grasp. The Swedish king was in need of experienced sea captains and, as with his army, he found some of them from across the North Sea.
The Swedish Navy had been created in the sixteenth century as a defensive force against invasion and blockade and as an offensive force for power projection in the Baltic. From the late seventeenth century it was primarily seen as a defence of the Swedish empire. It had to be able to control the sea lines of communication within the Baltic empire in order to provide quick reinforcements and supply to Swedish provinces and garrisons threatened by sudden attack. One cornerstone of this mobilisation system was the unusual way of manning the navy which remained unchanged up to the advent of steam. Apart from a permanent core of experienced seamen and trained gunners, most of the naval manpower was recruited from the coastal provinces close to Karlskrona. They had to provide the navy with (voluntarily recruited) men who might turn up at short notice in case of an emergency. Most of these men were not experienced seamen (although the navy gave them some training) and they were probably better gun-crews than top-sail men but they gave the Swedish Navy the most rapid mobilisation system in Europe. The same system was used for the oared flotillas based in Stockholm and Sveaborg. There was no system for recruiting or conscripting seamen from the mercantile marine. In spite of that it grew into one of the largest in Europe during the eighteenth century.
The Swedish Navy emerged from the Great War of 1700-21 seriously weakened. Materially, it recovered in the 1730s, but the Swedish government and armed forces failed to readjust to the new strategic conditions. The navy still regarded Denmark-Norway as the main enemy and plans for army-navy cooperation were inadequate. A considerable galley fleet had been created in the 1710s and it was maintained in Stockholm and Gothenburg after the war but, mentally, the navy had not adapted to the fact that it had an important role to play in amphibious warfare. The war with Russia of 1741-43 revealed these weaknesses. Close strategic and even tactical coordination of the battle fleet, the archipelago fleet and the army had again proved to be the key to Russian victory in Finland. The lesson was there to be learned by Sweden.
After the war a determined effort was made to create a large oared flotilla. During the political crisis around Sweden in the late 1740s no fewer than 44 galleys were built and the fortress base of Sveaborg (Suomenlinna) was founded outside Helsinki. Sweden now had enough oared craft to equal the Russians in archipelagic warfare, even when the eastern neighbour was at a high degree of readiness. In practice, the new large oared force meant that a considerable part of the Swedish Army should serve at sea and in the archipelagos during wars. Gradually innovative efforts, from 1760 led by the naval architect Frederick Henrik af Chapman, created new and more efficient types of oared vessels, primarily gunboats. The archipelago fleet was formally transferred to the army from 1756 but in practice it became a third armed force. The development of Sveaborg provided it with an adequate base close to the main operational area. The war of 1788-90 showed that the reforms had worked.
The Swedish battle fleet was maintained at a very even level (23-25 battleships) from the 1730s to 1790. Most battleships were built with well-seasoned timber and high-quality iron and enjoyed very long lives, usually with a mid-life great repair. The high age of many ships has often been misinterpreted as a sign of neglect. Actually, the battle fleet was kept in a high or at least adequate state of readiness during most of the eighteenth century. 16 Together with the archipelago fleet and the Sveaborg fortress it was also regarded as an important asset in Sweden’s efforts to get foreign subsidies to its armed forces, forces which were very large for a small and not very rich nation. During the eighteenth century, France became the most important supplier of finance and, at least in the 1770s and 1780s, this was primarily spent on the navy. After the severe losses against Russia in 1790 it was planned to rebuild the navy to a force of around 20 battleships with the help of new subsidies, but the times had changed and no Great Power had any interest in creating a strong Swedish battle fleet. During the Napoleonic Wars, Great Britain paid subsidies to Sweden but the British were mainly interested in keeping the Swedish Army in shape for Continental warfare. The Swedish battle fleet had to be maintained at a level of around a dozen units and the oared flotilla (cheap to maintain in peacetime) became a relatively more important part of the naval forces. The two navies had by now begun to fight about limited resources, a fight that would be an important part of Swedish naval policy-making for much of the nineteenth century.
The loss of Finland during the war of 1808-09 again changed the Swedish naval strategy. Sweden had now to cope with a situation where defence against sea-borne invasion from a power with a superior battle fleet was the most likely threat. The union with Norway did not change the basic strategic situation as the Norwegian parliament was not willing to recreate even a small part of the powerful battle fleet which Norway until recently had shared with Denmark. Gradually, Sweden- Norway opted for a cautious policy of non-alignment and neutrality. As events during the war period 1801-14 had shown, Scandinavia was now placed between the two superpowers Great Britain and Russia, and this was to mold strategic thinking in the Baltic for much of the nineteenth century.