U.S.S. Dunderberg (1865)
At the beginning of the Civil War, much European popular and government sympathy was with the Confederates, who appeared to be making a credible bid for independence. Overt aid to the agents of the South caused serious friction between the British and French on the one hand, and the Lincoln Administration on the other. For a time war with Britain seemed quite likely to many in Washington. The Dunderberg was born from the need to prepare for such a conflict -- one might be tempted to see in her the U.S.'s "answer" to HMS Warrior. Dunderberg was a made-up name meaning, in Low Swedish, Thunder Mountain -- surely the most poetic name given to any U.S. battleship.
Dunderberg was a seagoing casemate ironclad. At 377 feet, she was the longest wooden warship ever constructed. She was constructed by W.H. Webb Co. in New York -- a famous builder of packet and clipper ships. Extensive use of iron braces and other metal structural elements made possible the increased length of the hull. This technique was commonly used in large sailing and sail/steam warships of the mid-19th century, due to the decreased availability of large timber in Europe. it was impractical to build a wholly wooden ship longer than about 300 feet (91.4 m) because the members would work and sag from the stress of cutting through the waves -- a phenomenon known as "hogging". As the screws and piercings for attaching metal fixtures tended to rip and split the wooden frames, ships so constructed were not as long-lived as those constructed by traditional methods (fastening members together with wooden pegs or "treenails"). The new iron fastening technique was here taken to its limits, with predictable results.
Dunderberg's design was an elaboration of the CSS Virginia's, with higher freeboard and greater seaworthiness, adding a chisel-shaped 50-foot ram to the bow, and raising above the armored gundeck two tall masts bearing a hermaphrodite rig. The ship was intended for ramming and had extensive watertight subdivision for the 1860s: collision bulkheads and a double bottom. At 9 kts top speed, Dunderberg was too slow to be a dangerous ram against faster vessels, but she did carry a powerful battery at a speed suitable for close inshore action or harbor defense. Of course, her main feature was the long slope-sided casemate full of heavy artillery: 11-inch and 15-inch Dahlgrens. Built essentially of wood, Dunderberg was a true ironclad, in the original meaning of the word. As was standard in the 1860s, she carried 4½" of wrought-iron plate (backed by a foot of oak) over the entire gundeck, and 2½" armor on the exposed portions of the hull.
Circumstances can shift rapidly in war. The feared conflict with England did not materialize; and as Union diplomats and lobbyists urged their government's interests quite forcefully in Europe, European officials became accustomed to cooperating with them. As the Union began winning decisive victories such as Vicksburg and Gettysburg in 1863, and as the Confederate economy crumbled, sympathy for the secessionist cause eroded in Europe. In New York, construction of the Dunderberg slowed to a crawl while the government stepped up production of large monitors to win the riverine war. Dunderberg was launched (above) just after Lee's surrender ended the war. She completed late in 1865. The U.S. Navy refused delivery of the ship and returned her to her builders in October 1866.
It was time for the builders to capitalize, in turn, on Europe's insecurities and rumor of war. The 1860s were the age of nationalism on the Continent, marked by the unification of Italy under King Victor Emanuel of Naples and the rise of Prussia under the "Iron Chancellor," Prince Otto von Bismarck. Bismarck's influence rested on the threat of Prussian military might, but he was a statesman both subtle and cunning. Bismarck's passionate rhetoric in the Reichstag (such as his signature "Blood and Iron" speech) belied his crafty maneuvers that brought the German states into war in an advantageous posture again and again. During the decade Bismarck built Prussia's stature through a series of lightning wars: first with Denmark, then with the Habsburg Empire, and finally with France in 1870. Bismarck's method was a carefully plotted sequence of military blackmail, ruthless warmaking, and punitive peace.
Tensions between Germany and France were already in the air in 1866, when word went around that Bismarck was interested in acquiring the Dunderberg for the Prussian Navy. Napoléon III of France hastened to purchase the ship himself to keep it out of Bismarck's hands. So Dunderberg sailed transatlantic and was mustered into the Marine Nationale Française as le Rochambeau. Despite being rebuilt and rearmed starting in 1867, she had no effect on the outcome of the war. That was determined by a Prussian pincers movement encircling the French army at Sedan and compelling a surrender on September 1, 1870. Along with 20,000 French troops, German forces under Gen. von Moltke bagged Emperor Napoléon III. Still the war ground on for another 5 months, encompassing further defeats for the French, the overthrow of Napoléon's government, and the humiliating siege of Paris. Exacting a crippling indemnity from France, Bismarck used the victory as his platform for unifying Germany under his leadership in 1871. Surely his decision to crown Wilhelm I the German Emperor (Kaiser) in the Hall of Mirrors at Versailles was meant to mark the end of French ascendancy. Over the next 19 years, as Reich Chancellor, Bismarck energetically promoted German supremacy, building an industrial powerhouse that could challenge Britain, the leading European Power, and a military establishment which threw fear into all of Germany's rivals.
Louis Napoléon died in exile in Kent in 1873. Much had changed politically in a few years, and much had changed technologically as well. Obsolete after a scant 8 years in service, her over-long wooden hull already sagging, the war she was supposed to help win irretrievably lost, Dunderberg / Rochambeau was broken up in 1874. Her antiquated design had no influence on the French central battery ironclads which came out subsequently; rather, these responded directly to British designs. America was to let its navy decay for two decades following the Civil War, and perhaps it was as well so. This was the "Age of Indecision" when numerous battleship schemes were floated in Europe. There were many bizarre battleships built (and even more proposed) during the 1870s and 1880s; most of these schemes were made obsolete in only a few years by fast-breaking technological advances. Accordingly, a great amount of resources was tied up in projects of short-lived value; with its severely limited naval budget, the U.S. was well out of this competition, and made a gradual re-entry in the 1880s and 1890s when capital ship design was becoming more standardized.
Specifications for the Dunderberg:
Dimensions: 377.3' x 72'8" x 21' Displacement: 7,060 tons. Armament: (4) 15" Dahlgren SB; (11) 11" Dahlgren SB. Armor: Wrought-iron type. 4.5" casemate, 2.5" belt. Rating: Ironclad frigate. Propulsion: Coal-fired boilers; (2) direct acting steam engines shafted to twin screw. Sail rig: Topsail schooner. Maximum speed: 9 kts. Crew: 410.
Metric specs:
Dimensions: 115m x 22.2m x 6.4m Displacement: 7,060 tons. Armament: (4) 381 mm Dahlgren SB; (11) 280 mm Dahlgren SB. Armor: Wrought-iron type. 114 mm casemate, 64 mm belt. Rating: Ironclad frigate. Propulsion: Coal-fired boilers; (2) direct acting steam engines shafted to twin screw. Sail rig: Topsail schooner. Maximum speed: 16.7 km/hr. Crew: 410.
A wood-engraving of Dunderberg at sea, published 1866.
A CAD rendering of Dunderberg in perspective.
