SMS Friedrich Carl was an ironclad warship built for the Prussian Navy in the mid-1860s. The ship was constructed in the French Societé Nouvelles des Forges et Chantiers shipyard in Toulon; her hull was laid in 1866 and launched in January 1867. The ship was commissioned into the Prussian Navy in October 1867. The ship was the third ironclad ordered by the Prussian Navy, after and , though the fourth ship to be acquired, , was ordered after but commissioned before Friedrich Carl. Friedrich Carl served with the fleet from her commissioning in 1867 until 1895, when she was removed from front-line service to serve as a training ship. During the Franco-Prussian War in 1870–1871, the ship formed part of the main German squadron commanded by Vizeadmiral (Vice Admiral) Eduard von Jachmann. Engine trouble, however, plagued the ship and two of the other three vessels in the squadron; as a result, they made only two sorties from the port of Wilhelmshaven to challenge the French blockade. Neither resulted in combat. Friedrich Carl was also deployed to Spain during an insurrection in 1873, during which she assisted in the seizure of three rebel vessels in two engagements. The ship was refitted at the Imperial Dockyard in Wilhelmshaven in the 1880s. She was renamed Neptun in 1902 and used as a harbor ship until June 1905, when she was removed from the naval register. The following year, she was sold to ship breakers in the Netherlands and dismantled for scrap. Design Following the acquisition of the small ironclad warships and , which were only usable in coastal areas, the Prussian Navy sought to acquire armored vessels capable of operations on the high seas. The purpose of the new ships would be primarily directed against Prussia's primary naval rival, Denmark, which in the recent Second Schleswig War had imposed a blockade of German ports that Prussia had not been able to break. Ironclads were at that time a recent development and the only option for sea-going warships was the armored frigate, modeled on traditional sailing ships with a battery on the broadside. The navy requested approval from the (Parliament) in 1865 for an expanded budget to acquire the needed vessels, but the parliament refused, prompting King Wilhelm I to circumvent the legislature with a decree on 4 July authorizing the purchase of two armored frigates. At that time, Britain and France had the