• Type: Passaic-Class Single Turret Monitors
• Designer: John Ericsson
• Hull: Iron
• Length: 190 feet
• Beam (Width): 37 feet
• Displacement: 1,335 tons
• Draft: 11 1/2 feet
• Speed: 4 1/2 knots average; 7 knots max
• Crew: 70 to 88 officers & men
• Armor: 11" turret, 5" sides, 1" deck, 8" pilothouse
• Engines: 340 HP 2-cycle Ericsson vibrating-lever (trunk) engine (40" X 1'10") 
• Boilers: Two; Martin's
• Propulsion: Two screws
• Ships in Class: U.S.S. Passaic, U.S.S. Patapsco, U.S.S. Nahant, U.S.S. Montauk, U.S.S. Sangamon, U.S.S. Weehawken, U.S.S. Nantucket, U.S.S. Catskill, U.S.S. Lehigh

The Passaic Class of monitor ships featured thicker hull plating, larger guns, better steering, and an improved pilot house design. The new monitors were larger than the original, measuring 200 feet by 45 feet in the beam. The hull, designed with more shiplike lines, in contrast to the original monitor's nearly flat bottom. The most noticeable change was to the pilot house, which was enlarged to six feet in diameter and mounted atop the turret.

USS PASSAIC: 

• Built By: Continental at Greenpoint, NY
• Authorized: March 17, 1862
• Launched: August 30, 1862
• Commission: November 25, 1862
• Cost: $400,000
• Decommission: June 16, 1865
• Weapons: One 15-inch & one 11-inch Dahlgren smoothbore guns (Nov 1862-Late 1864); 1 15-inch Dahlgren smoothbore gun, 1 150-pdr Parrott rifled gun (Late 1864, 1865)
• Commanders: Capt. Percival Drayton (Dec 62-May 63) LtCdr. Edward Simpson (Jun 63-May 64), LtCdr. T. Scott Fillebrown (Jun 64-Jan 65), LtCdr. Robert W. Scott (Feb-Mar 65), Cdr. Edward T. Nichols (Apr 65) LtCdr. Williams (May 65)
• Current Disposition:  Broken up October 10, 1899
• Service History: Constructed by Continental at Greenpoint NY. Launched 30 Aug 62. Commissioned 25 Nov 62. Assigned to NABS. On trip south, engine failed and was towed to Washington for repairs. Assigned to SABS; was to have been sent to Wilmington to attack Fort Caswell with Monitor, but that was canceled when that ship foundered. Arrived at Port Royal 21 Jan 63. Ordered to Wassaw Sound to guard against CSS Atlanta 26 Jan 63. Reconnoitered up Wilmington River after Atlanta until stopped by shallow water 1 February 63. Captured schooner Glide 23 Feb 63. Ordered to Ossabaw Sound 27 Feb 63. Bombarded Fort McAllister on 3 March 63, struck 34 times (deck damaged). Withdrew to Port Royal 4 Mar 63. Ordered to North Edisto River 1 Apr 63. Bombarded Fort Sumter on 7 April 63, struck 35 times (11" gun disabled, turret jammed). Withdrew to Port Royal. Ordered to North Edisto River 18 Apr 63. Ordered to New York 27 Apr 63, arrived 4 May 63. Repaired at New York in May-July 63. Bombarded New Smyrna FL 28 July 63. Operations against Charleston from 18 July 63 to 9 November 93; grounded near Fort Sumter 22 August 63, shelled CSS Presto near Fort Moultrie 2 February 64. Decommissioned 16 June 65. Wooden deck beams replaced with iron 1871, overhauled 1872. 11" gun replaced with second 15" gun 1873. Recommissioned 1876. Receiving ship at Washington DC from 1878 to 1882, at Annapolis from 1883 to 1892, and at Boston from 1893 to 1894, then decommissioned. Recommissioned briefly for harbor defense 1898. Sold to breakers 10 Oct 99.