SMS König Wilhelm [a] (King William) was an armored frigate of the Prussian and later the German Imperial Navy.

The ship was the fifth ironclad ordered by the Prussian Navy, after Arminius, Prinz Adalbert, Friedrich Carl, and Kronprinz.

In May of that year, she was placed out of active service and used as a floating barracks and training ship, a role she held through World War I.

The ship had originally been ordered by the Ottoman Empire under the name Fatih from the Thames Ironworks shipyard in London, England in 1865.

The Kingdom of Prussia had embarked on a program to acquire sea-going ironclad warships, and after having placed orders for two such vessels in British and French shipyards in 1865, opted to add Fatih to the Prussian Navy when the opportunity arose.

[3] This was in part due to the fact that Germany laid down only one small ironclad between 1876 and 1888;[4] the four Brandenburg-class battleships, launched in 1891 and 1892, were the first ships to surpass König Wilhelm in size.

[6] König Wilhelm was noted by the German navy as having had "satisfactory sea-keeping qualities";[7] the ship was responsive to commands from the helm and had a moderate turning radius.

[7] A horizontal, two-cylinder single-expansion steam engine, built by Maudslay, Son & Field of London, powered the ship.

These were divided into two boiler rooms with twenty fireboxes in each, supplied steam to the engine at 2 standard atmospheres (200 kPa).

The ship carried 750 t (740 long tons) of coal, which enabled a maximum range of 1,300 nautical miles (2,400 km; 1,500 mi) at a cruising speed of 10 knots (19 km/h; 12 mph).

[10] Shortly after entering service, she joined the ironclads Friedrich Carl and Kronprinz for training exercises in August and September.

König Wilhelm, Kronprinz, and Prinz Adalbert continued on to Plymouth while Friedrich Carl returned to Kiel for repairs.

The latter vessel quickly rejoined the ships there and on 1 July they departed for a training cruise to Fayal in the Azores, Portugal.

While they cruised east through the English Channel, they learned of the increasing likelihood of war, and the Prussians detached Prinz Adalbert to Dartmouth to be kept informed of events.

The rest of the squadron joined her there on 13 July, and as war seemed to be imminent, the Prussians ended the cruise and returned to home.

[12][13] The four ships, under the command of Vizeadmiral (Vice Admiral) Eduard von Jachmann, made an offensive sortie in early August 1870 out to the Dogger Bank, though they encountered no French warships.

König Wilhelm and the other two broadside ironclads thereafter suffered from chronic engine trouble, which left Arminius alone to conduct operations.

[14] König Wilhelm, Friedrich Carl, and Kronprinz stood off the island of Wangerooge for the majority of the conflict, while Arminius was stationed in the mouth of the Elbe river.

[15] On 11 September, the three broadside ironclads were again ready for action; they joined Arminius for another major operation into the North Sea.

General Albrecht von Stosch became the chief of the Imperial Navy, and organized the fleet for coastal defense.

[16] Through the early 1870s, König Wilhelm and the other armored frigates operated intermittently, alternating between periods of training activity and stints in reserve.

For the 1875 training year, König Wilhelm cruised with Kronprinz and the recently completed ironclads Hansa and Kaiser, though they stayed in local waters.

[18] While steaming in the Straits of Dover on 31 May,[19] König Wilhelm accidentally collided with the newly commissioned turret ironclad Grosser Kurfürst.

[20] A failure to adequately seal the watertight bulkheads aboard Grosser Kurfürst caused the ship to sink rapidly,[19] in the span of about eight minutes.

[22] In the aftermath of the collision with Grosser Kurfürst, the German navy held a court martial for Rear Admiral Batsch, the squadron commander, and Captains Monts and Kuehne, the commanders of the two ships, along with Lieutenant Clausa, the first officer aboard Grosser Kurfürst, to investigate the sinking.

Kaiser Wilhelm II attended the ceremony, as did Ludwig von Henk, who had by that time retired as a Vizeadmiral.

[28] In 1895, König Wilhelm went into drydock at the Blohm and Voss shipyard in Hamburg for an extensive reconstruction into an armored cruiser.