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Passaic-class monitor
USS Passaic.jpg
USS Passaic during gunnery tests in the Hudson River, N.Y., November 1862
Class overview
Builders: Continental Iron Works
Harlan & Hollingsworth
Harrison Loring
Reaney, Son & Archbold
Donohue, Ryan & Secor
Atlantic Iron Works
Preceded by: USS Monitor
Succeeded by: Canonicus class
In commission: 25 November 1862 - 1899
Completed: 10
Lost: 2
USS Weehawken, foundered 6 December 1863
USS Patapsco, mined 15 January 1865
General characteristics
Displacement: 1,875  tons
Length: 200 ft (61 m) overall
Beam: 46 ft (14 m)
Draught: 10 ft 6 in (3.20 m)
Propulsion: 2 Martin boilers, 1-shaft Ericsson vibrating lever engine, 320  ihp (235  kW)
Speed: 7  knots
Complement: 75
Armament: 1 × 15  in (381  mm) smoothbore
1 × 11  in (279  mm) smoothbore
Lehigh, Patapsco:
1 × 15  in (381  mm) smoothbore
1 × 8  in (203  mm) Parrott rifle
2 × 15  in (381  mm) smoothbore
Armor: Iron
Side: 5 - 3  in (12.7 - 7.6  cm)
Turret: 11  in (27.9  cm)
Deck: 1  in (2.5  cm)

The Passaic-class ironclad monitors of the U.S. Navy saw service in the U.S. Civil War and the Spanish-American War. The last such monitor was stricken from the Navy List in 1937.


Naval architect and engineer John Ericsson designed the Passaic-class warships, drawing upon lessons learned from the first USS Monitor, which he also designed. The Passaic monitors were larger than the original Monitor and had their pilothouses atop the turret, rather than near the bow. This allowed a wider field of view and easier communications between captain, pilot and crew. The shape of the hull was an improvement with a less pronounced overhang than the Monitor. The Passaic class featured an 18 ft (5.5 m) funnel and improved ventilation.

The turret was 21 ft (6.4 m) in diameter inside with the 15 in (380 mm) gun mounted flush. As a result, the 15 in gunners could not see their targets and had to aim with the 8 in (200 mm) or 11 in (280 mm) guns. The Lehigh had her 11 inch smoothbore replaced with an 8 inch Parrot. The Passaic also had this modification by July 1863, and, eventually, all surviving members of this class had an additional 15 inch smoothbore added.

Later improvements included an additional 50 tons of deck plating over the magazines and machinery spaces as well as rings fitted around the turret and pilot houses.

Officers of a Union monitor, probably USS Patapsco, photographed during the American Civil War.

Ships in class

Warships of Passaic class included:

The first ship of the class was named for the town of Passaic, New Jersey.

See also

  • Uragan-class monitor, an Imperial Russian Navy monitor type built to the plans of the American Passaic class.


  • Canney, Donald L. (1993). The Old Steam Navy: The Ironclads, 1842–1885. 2. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-586-8. 
  • Gibbons, Tony (1989). Warships and Naval Battles of the Civil War. New York: Gallery Books. ISBN 0-8317-9301-5. 
  • Olmstead, Edwin; Stark, Wayne E.; Tucker, Spencer C. (1997). The Big Guns: Civil War Siege, Seacoast, and Naval Cannon. Alexandria Bay, New York: Museum Restoration Service. ISBN 0-88855-012-X. 
  • Silverstone, Paul H. (2006). Civil War Navies 1855-1883. The U.S. Navy Warship Series. New York: Routledge. ISBN 0-415-97870-X. 

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