Table:
text: Canonicus-class monitor
Ships
Ships
Ship Builder Namesake Renamed Laid_down Launched Commissioned_or_completed_
Ajax Snowden & Mason, Pittsburgh, Pennsylvania Manayunk, Philadelphia Manayunk, 1862; Ajax, 15 June 1869 1862 18 December 1864 27 September 1865*
Canonicus Harrison Loring, Boston, Massachusetts Canonicus Scylla, 15 June 1869; Canonicus, 10 August 1869 1862 1August1863 16 April 1864
Catawba Alexander Swift & Company, Cincinnati, Ohio Catawba River Atahualpa 1862 13 April 1864 10 June 1865*
Mahopac Secor & Co., Jersey City, New Jersey Lake Mahopac Castor, 15 June 1869; Mahopac, 10 August 1869 1862 17 May 1864 22 September 1864

text: Canonicus-class monitor
Ships
Ships
Ship Builder Namesake Renamed Laid_down Launched Commissioned_or_completed_
Manhattan Perine, Secor & Co., Jersey City, New Jersey Manhattan Indians Neptune, 15 June 1869; Manhattan, 10 August 1869 1862 14October1863 6 June 1864
Oneota Alexander Swift & Company, Cincinnati, Ohio Oneota Tribe of the Sioux Indians Manco Cápac 1862 21 May 1864 10 June 1865*
Saugus Harlan & Hollingsworth , Wilmington, Delaware Saugus, Massachusetts Centaur, 15 June 1869; Saugus, 10 August 1869 1862 8 February 1864 27 August 1864
Tecumseh Charles Secor & Co., Jersey City, New Jersey Tecumseh Not Applicable 1862 12 September 1863 19 April 1864

Question: What is the minimum requirement for a Canonicus class monitor?