Namesake: Lake Mahopac, New York

Ordered: 15 September 1862

Builder: Secor & Co., Jersey City, NJ

Laid Down: 1862

Launched: 17 May 1864

Commissioned: 22 September 1864

Decommissioned: June 1865

Recommissioned: 15 January 1866

Renamed: Castor, 15 June 1869

Renamed: Mahopac, 10 August 1869

Decommissioned: 11 March 1872

Recommissioned: 21 November 1873

Out of Service: In ordinary 1889-1895

Stricken: 14 January 1902

Fate: Sold, 25 March 1902

​

Characteristics

​

Class & Type: Canonicus-class monitor

Displacement: 2,100 long tons

Tonage: 1,034 tons

Length: 225 ft. 

Beam: 43 ft. 3 in.

Draft: 13 ft. 6 in.

Installed Power: 320 ihp

2 x Stimers fire-tube boilers

Propulsion: 1 x Propellor

1 x Vibrating-lever steam engine

​

​