Naval History and Heritage Command

Naval History and Heritage Command

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Oneota I (Monitor)

(Monitor: displacement 2,100 tons; length 225'; beam 43'3"; dr. 11'6"; speed 13 knots; complement 100 (approx.) ; armament 2 15-inch Dhalgren smooth bore cannons; class Canonicus)

A tribe of Sioux which occupied lands in what is now Nebraska.


Oneota, a harbor and river monitor built by Alexander Swift & Co., Cincinnati, Ohio, was launched 21 May 1864 and completed shortly after the end of the Civil War on 10 June 1865.

Laid up at Mound City, Ill., with most of the retired Union warships, the monitor remained there until sold back to her builder, Alex Swift and Co., on 13 April 1868. Around that same time, the Peruvian government made an offer to purchase Oneota (as well as Catawba) but the transaction was held up owing to disputes over the applicability of U.S. neutrality laws regarding armament sales to South America. Continued legal wrangling, and the need to repair deterioration suffered by the monitors while in storage, kept the monitors at New Orleans until the summer of 1869 when the ships finally sailed south to Peru.

Named for the founder of the Kingdom of Cuzco, which eventually became the Inca Empire, the monitor served in the Peruvian Navy as Manco Capac. In 1879, after the outbreak of war between Chile and Peru, Manco Capac served at Callao and Arica, defending those ports against attack by Chile. In February, Chilean forces landed near Arica and took the hinterlands after some months of operations. Following the Chilean victory at the Battle of Tacna on 26 May 1880, Arica was exposed and the city was stormed on 7 June. Manco Capac was scuttled to avoid capture. The wreck was discovered in 2007, located several miles off the coast in about 100 feet of water.

Corrected by Dr. Timothy L. Francis, 30 August 2007

Published: Mon Aug 17 12:35:22 EDT 2015