The Océan-class ironclads were a class of three wooden-hulled armored frigates built for the French Navy in the mid to late 1860s.

Océan attempted to blockade Prussian ports in the Baltic Sea in 1870 during the Franco-Prussian War and Marengo participated in the French conquest of Tunisia in 1881.

[2] The ships were over-weight as completed; their draught so exceeded that designed for them that an increase of stability by ballast was impossible.

[3] The Océan-class were reported to be able to carry all sail safely, were good sea-boats, steady and well-behaved, but lacking in stiffness (resistance to heeling).

[2] On sea trials the engines produced between 3,600–4,100 indicated horsepower (2,700–3,100 kW) and the ships reached 13.5–14.3 knots (25.0–26.5 km/h; 15.5–16.5 mph).

[4] The Océan-class ships were barque or barquentine-rigged with three masts and had a sail area around 2,000 square meters (22,000 sq ft).

[5] They also had a secondary armament mounted on the broadside on the spar deck of six 12 cm (4.7 in) guns,[5][7] the rear pair could be moved to the stern to fire aft.

[14] During the Franco-Prussian War of 1870–71 Océan was assigned to the Northern Squadron that attempted to blockade Prussian ports on the Baltic until recalled on 16 September 1870 and ordered to return to Cherbourg.

Océan was assigned to the Gunnery School that same year and later became a training ship for naval apprentices before being condemned in 1894.

[1] Marengo was running her sea trials when the Franco-Prussian War began and was immediately put in reserve.

[17] Suffren was placed into reserve after she completed her sea trials and was not commissioned until 1 March 1876 when she became flagship of the Cherbourg Division.

On 1 September 1880[12] the ship was assigned to the division that participated in the international naval demonstration at Ragusa later that month under the command of Vice Admiral Seymour of the Royal Navy in an attempt to force the Ottoman Empire to comply with the terms of the Treaty of Berlin and turn over the town of Ulcinj to Montenegro.