SMS Preussischer Adler was a paddle steamer originally built in the mid-1840s for use on a packet route between the Kingdom of Prussia and the Russian Empire in the Baltic Sea.

Preussischer Adler was sent to the Mediterranean Sea in September 1863 in company with a pair of gunboats, but shortly after they arrived, they were recalled owing to an increase in tension between Prussia and Denmark that resulted in the Second Schleswig War.

The combined squadron attacked a Danish force enforcing a blockade of the German North Sea ports, resulting in the Battle of Heligoland in May 1864.

[2][3] Her propulsion system consisted of one horizontal, 2-cylinder, single-expansion marine steam engine that drove a pair of paddle wheels, one on each side of the ship.

Continued pressure forced the postal service to transfer the vessels, and upon her requisitioning, her deck was reinforced to support the weight of the guns added.

The senior naval officers convened a committee on 5 September to evaluate the vessel; since the Russia–Prussia postal line could not be reestablished owing to the uncertain political situation in the Baltic Sea, the navy initially opted to decommission Preussischer Adler.

But after Denmark remobilized its forces in February 1849 to resume the conflict with the Duchy of Schleswig, the navy decided to return the ship to active service, and at this time the two 32-pounder guns were added.

The ship was recommissioned in May, with Barandon again in command; by this time, he had been inducted into the Prussian Navy and given the rank Leutnant zur See (Lieutenant at Sea).

A secondary purpose of the cruise was to patrol the mouth of the Danube at Sulina on the Black Sea, a right granted to Prussia and the other European Great Powers (excluding Russia) under the terms of the Treaty of Paris that had ended the Crimean War in 1856.

From there, they passed through the Dardanelles and Bosporus into the Black Sea to patrol the Danube, but they remained there only briefly before receiving orders to return home on 3 December owing to the rise in tensions between Denmark and the German states.

Boiler problems aboard Preussischer Adler, coupled with heavy coal usage, slowed the voyage back to Prussia, and they had only reached Brest, France by 3 February 1864, by which time war had again broken out between Denmark and the German Confederation.

To assist the Prussians, the Austrian Navy sent Kommodore Wilhelm von Tegetthoff with the screw frigates Schwarzenberg and Radetzky to break the Danish blockade.

By 15 February, the Prussians had ascertained that the Danish Navy had sent only the screw frigate Niels Juel into the English Channel, so the naval command ordered Klatt to return home.

There they waited until Tegetthoff's frigates arrived, joining forces to make the last and most dangerous leg of the trip back to Cuxhaven.

[9] On the morning of 9 May, Tegetthoff learned that a Danish squadron consisting of the steam frigates Niels Juel and Jylland and the corvette Hejmdal were patrolling off the island of Heligoland.

[14] Preussischer Adler and the other Prussian ships remained on the disengaged side of the Austrian frigates, taking shots at the Danish vessels when possible, though they had little success.

After Schwarzenberg caught fire, Tegetthoff broke off the action and escaped to the neutral waters around Heligoland, where the ships remained until early the next day.

Though the Danish squadron had won a tactical victory at Heligoland, the arrival of Austrian warships in the North Sea forced the Danes to withdraw their blockade.

[9][17] The war ended in a Danish defeat with the Treaty of Vienna on 30 October, and thereafter repair work began on Preussischer Adler's troublesome boilers.

Preussischer Adler then carried the Prussian officers back to Kiel and immediately took aboard King Wilhelm I, Frederick Francis II, Grand Duke of Mecklenburg-Schwerin, and Carl Scheel-Plessen, the new president of the Province of Schleswig-Holstein.

[19] On 20 January 1869, Preussischer Adler carried material to be used in completing the new armored frigate König Wilhelm, then being built at the Thames Iron Works in London.

Preussischer Adler remained in London at the disposal of the acceptance commission during the final months of work on König Wilhelm and she escorted the ironclad back to Kiel on 4 May.

[20] She was mobilized after the outbreak of the Franco-Prussian War in July and she served as the flagship of Konteradmiral (Rear Admiral) Eduard Heldt, the commander of the Marinestation der Ostsee (Naval Station of the Baltic Sea).

The French Navy sent a squadron into the Baltic, but poor planning hampered its effectiveness: it possessed no landing forces and few shallow-draft vessels suitable for operations close to shore.

The next month, she carried Prince Friedrich Karl from Flensburg to Heiligenhafen, and in mid-August, the ship was transferred from Kiel to Wilhelmshaven, where she continued to serve as a tender.

Prince Adalbert, the Inspector General of the Navy, boarded Preussischer Adler for his last cruise in the North and Baltic Seas in September; at the conclusion of the voyage, the ship returned to Wilhelmshaven, where she was decommissioned.

She served as a fishery protection vessel again in July that year, thereafter seeing short periods in her training role between 1875 and 1877, ultimately being decommissioned for the last time on 30 April 1877.

KL Alfred von Tirpitz, the new head of the torpedo department, wanted to test the effectiveness of the weapons on an iron-hulled vessel.