Henk was born in Anklam, Province of Pomerania. He began his career in merchant ships, making journeys to Brazil, the Mediterranean, and the Black Sea. In 1844, he was promoted to Captain. After the establishment of the Prussian Navy in 1849, he entered as an auxiliary officer, becoming a Kapitänleutnant in 1855 and a Korvettenkapitän in 1859. From August to October 1858, he commanded the aviso. In 1861 he went to Berlin as the head of the Hydrographic Bureau in the Prussian War Ministry. In 1865, he became captain of the steam corvette, which was sent to the Mediterranean. During the Austro-Prussian War of 1866, Henk was commander of the Prussian North Sea Fleet. Over the winter of 1866–1867, Henk commanded the steam frigate on a cruise to the Mediterranean, in company with the gunboat. Gazelle struck a merchant ship in Constantinople in February 1867; Henk had been asleep at the time of the collision and the investigation placed the blame for it on his executive officer, KL Johannes Weickhmann. The Admiralty recalled aGazelle in April due to the damage sustained in the accident. In 1867 was promoted to the rank of Kapitän zur See. During the Franco-Prussian War of 1870–1871, he commanded the armored frigate, part of the North Sea squadron commanded by Konteradmiral Eduard von Jachmann. The Prussian fleet sortied only twice to attack the French blockade fleet in the North Sea, in early August and 11 September 1870, but on both occasions the fleet failed to locate any French vessels. For much of the war, König Wilhelm struggled with machinery problems that left her confined to port. After war's end became commander of the Marinestation der Nordsee. In 1871, he was promoted to flag rank as Konteradmiraland was ordered to Berlin as Director of the Admiralty the following year, where he served as the deputy to Albrecht von Stosch, the chief of the Admiralty. Henk was chosen in large part to reduce the threat to the position of Stosch, a general of the Prussian Army with no naval experience. Henk was an officer of middle-class background, had initially served in the merchant marine before entering the navy, and though he had been exonerated by the investigation into the Gazelle collision, it nevertheless had damaged his reputation. Later in 1872, the idea for establishing a permanent "flying squadron" of cruising warships to respond to crises around the world was raised, but Henk rejected it on the grounds that it was excessively expensive; Stosch sided with Henk and the proposal came to nothing. For the majority of his tenure as Director of the Admiralty, Henk was restricted to technical matters after 1874 in a move by Stosch to further limit the challenge Henk might pose to him. As a result, he had authority only on matters of ship building, ordnance, and supply. He remained there until July 1879. During this time he was promoted further to Vizeadmiral, and the following year was raised to the hereditary peerage. He retired in 1879 and was given a pension. Between 1890 and 1893, Henk served in the Reichstag as a member of the German Conservative Party, representing the electoral district of Ueckermünde-Wollin. He died in Berlin.
