{{Short description|Early US ironclad warship type}} {{more footnotes|date=February 2013}} {{Infobox ship |section1={{Infobox ship/image |image=Monitor "Lehigh", James River - NARA - 525059.jpg |image_caption=USS ''Lehigh'' on the James River }}

|section2={{Infobox ship/class overview |name= |builders=*{{nobreak|Continental Iron Works (Greenpoint, NY)}} * Harlan & Hollingsworth * Harrison Loring * Reaney, Son & Archbold * Donohue, Ryan & Secor * Atlantic Iron Works |operators= |class_before={{USS|Monitor}} |class_after={{sclass|Canonicus|monitor|4}} |subclasses={{sclass|Uragan|monitor|4}} |cost= |built_range= |in_service_range= |in_commission_range=25 November 1862 – 1899 |total_ships_building= |total_ships_planned= |total_ships_completed=10 |total_ships_canceled= |total_ships_active= |total_ships_laid_up= |total_ships_lost=2 |total_ships_retired= |total_ships_preserved= }}

|section3={{Infobox ship/characteristics |hide_header= |header_caption= |type=Monitor |displacement=1,335&nbsp;tons |tons_burthen=844 (bm)<ref>Silverstone, p. 5</ref> |length={{convert|200|ft|m|abbr=on}} overall |beam={{convert|46|ft|m|abbr=on}} |height= |draught={{convert|10|ft|6|in|m|abbr=on}} |draft= |depth= |hold_depth= |decks= |deck_clearance= |ramps= |ice_class= |power= |propulsion=2 Martin boilers, 1-shaft Ericsson vibrating lever engine, {{convert|320|ihp|lk=in|abbr=on}} |sail_plan= |speed={{convert|7|kn|lk=in}} |range= |endurance= |complement=75 |sensors= |EW= |armament=*1 × {{convert|15|in|mm|adj=on}} smoothbore Dahlgren gun * 1 × {{convert|11|in|mm|adj=on}} smoothbore Dahlgren gun * '''Lehigh, Patapsco:''' * 1 × {{convert|15|in|mm|adj=on}} smoothbore Dahlgren gun * 1 × {{convert|8|in|mm|adj=on}} Parrott rifle * '''Camanche:''' * 2 × {{convert|15|in|mm|adj=on}} smoothbore Dahlgren guns |armour= |armor=*Iron * Side: {{convert|3|-|5|in|mm|abbr=on}} * Turret: {{convert|11|in|mm|abbr=on}} * Deck: {{convert|1|in|mm|abbr=on}} |aircraft= |aircraft_facilities= |notes= }} }}

The '''''Passaic''-class ironclad monitors''' of the U.S. Navy saw service in the U.S. Civil War and the Spanish–American War. The class was an improved version of the {{USS|Monitor}} equipped with a 15-inch Dahlgren gun in place of one of the 11-inch guns.<ref>Silverstone, p. 5</ref>

==Design== thumb|left|upright| Picture by Taylor and Huntington as being the turret of USS ''Monitor''; in fact the turret is of a ''Passiac''-class monitor-possibly that of USS ''Lehigh'' [[File:Uss Montauk 1862.jpg|thumb|left|USS ''Lehigh'' and USS ''Montauk'' in the Philadelphia Navy Yard, circa 1902]]

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 the captain, pilot and crew. The shape of the hull was an improvement; a fuller and rounder lower hull, far more boat-like than that of the ''Monitor'', and with a less pronounced overhang. The ''Passaic'' class featured an {{convert|18|ft|m|abbr=on}} funnel and improved ventilation. In combination, the significant hydrodynamic refinements and improved draught to the boilers resulted in a one-knot speed increase over the prototype monitor, despite the ''Passaic'' having a '''lower''' specific power than ''Monitor'' (''Passaic'' being almost 400 tons heavier and yet with the same 320ihp-rated machinery).

Having observed the new 15-inch Rodman cannon in fortifications and disappointed with the performance of the 11-inch Dahlgren versus {{ship|CSS|Virginia}}, Assistant Secretary of the Navy Gustavus Fox required the new monitors to be equipped with at least one gun of 15-inch caliber, resulting in rush production of a new 15-inch Dahlgren.<ref>Tucker, ''Arming the Fleet'' pp. 218–220</ref><ref>Olmstead, ''The Big Guns'', p. 91</ref> The turret was {{convert|21|ft|m|abbr=on}} in diameter inside with the {{convert|15|in|mm|abbr=on}} gun mounted flush because the muzzle diameter was too large for the turret opening. The large volume of propellant gases released inside the turret required the addition of a "smoke box" at the muzzle in the interior of the turret.<ref>Olmstead, ''The Big Guns'', p. 94</ref> As a result, the 15 in gunners could not see their targets and had to aim with the {{convert|8|in|mm|abbr=on}} or {{convert|11|in|mm|abbr=on}} guns. ''Lehigh'' had her 11-inch smoothbore replaced with an 8-inch Parrott rifle. ''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 to prevent their pivoting machinery from being jammed by shot.

==Ships in class== Warships of ''Passaic'' class included:

* ''Passaic'' * ''Montauk'' * ''Nahant'' * ''Patapsco'' * ''Weehawken'' * ''Sangamon'' * ''Catskill'' * ''Nantucket'' * ''Lehigh'' * ''Camanche''

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

==See also== * {{sclass|Uragan|monitor|1}}, an Imperial Russian Navy monitor type built to the plans of the American ''Passaic'' class.

==Notes== {{reflist}}

==References== {{Commons category|Passaic-class monitors}} * {{cite book|last=Canney|first=Donald L.|title=The Old Steam Navy: The Ironclads, 1842–1885|publisher=Naval Institute Press|location=Annapolis, Maryland|date=1993|volume=2|isbn=0-87021-586-8}} * {{cite book|last=Gibbons|first=Tony|title=Warships and Naval Battles of the Civil War|year=1989|publisher=Gallery Books|location=New York|isbn=0-8317-9301-5}} * {{cite book|last1=Olmstead|first1=Edwin|last2=Stark|first2=Wayne E.|last3=Tucker|first3=Spencer C.|title=The Big Guns: Civil War Siege, Seacoast, and Naval Cannon|publisher=Museum Restoration Service|location=Alexandria Bay, New York|year=1997|isbn=0-88855-012-X}} * {{cite book|last=Silverstone|first=Paul H.|title=Civil War Navies 1855–1883|publisher=Routledge|location=New York|year=2006|series=The U.S. Navy Warship Series|isbn=0-415-97870-X}} * {{cite book|last=Tucker|first=Spencer C.|author-link=Spencer C. Tucker |title=Arming the Fleet: U.S. Naval Ordnance in the Muzzle-Loading Era|publisher=Naval Institute Press|location=Annapolis, Maryland|year=1989|isbn=0-87021-007-6}} *{{cite journal|last1=Wright|first1=Christopher C.|title=''Canonicus'' at Jamestown, 1907|issn=0043-0374 |journal=Warship International |date=June 2021 |volume=LVIII |issue=2 |pages=126–162}}

{{Passaic class monitor}} {{Union ironclads}}

Category:Monitor classes Category:Passaic-class monitors