Passaic-class monitor


The Passaic-class ironclad monitors of the U.S. Navy saw service in the U.S. Civil War and the Spanish–American War. This highly successful class was an improved version of equipped with a 15-inch Dahlgren gun in place of one of the 11-inch rifles.

Design

Naval architect and engineer John Ericsson designed the Passaic-class warships, drawing upon lessons learned from the first, 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 Monitor. The Passaic class featured an funnel and improved ventilation.
Having observed the new 15-inch Rodman cannon in fortifications and disappointed with the performance of the 11-inch Dahlgren versus, 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. The turret was in diameter inside with the 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. As a result, the 15 in gunners could not see their targets and had to aim with the or guns. Lehigh had her 11-inch smoothbore replaced with an 8-inch Parrot. 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:
The first ship of the class was named for the town of Passaic, New Jersey.