Miantonomoh class monitor

USS Miantonomoh (1863).jpg
USS Miantonomoh in Washington Navy Yard, 1865.
Class overview
Builders: Portsmouth Navy Yard
New York Navy Yard
Boston Navy Yard
Philadelphia Navy Yard
In commission: 4 October 1864 - 1872
Completed: 4
General characteristics
Type: Monitor
Displacement: 3,400 long tons (3,455 t)
Length: 258 ft 6 in (78.79 m)
Beam: 52 ft 9 in (16.08 m)
Draft: 12 ft 8 in (3.86 m)
Propulsion: 4 Martin boilers, 2 shafts,
Agamenticus, Monadnock:
Ericsson vibrating lever engine
Miantonomoh, Tonawanda:
horizontal return connecting rod engine, 1,400 ihp (1,044 kW)
Speed: 9–10 knots (17–19 km/h; 10–12 mph)
Complement: 150
Armament: 4 × 15 in (380 mm) smoothbore Dahlgren guns (2×2)
Armor: Iron
Side: 5 in (130 mm)
Turrets: 10 in (250 mm)
Deck: 1.5 in (38 mm)

The Miantonomoh class monitors of the U.S. Navy were constructed during the U.S. Civil War, but only one ship of the class actually took part in it. They were broken up in 1874/5.

The ships of this class were designed by the Bureau of Construction and Repair, and were wooden-hulled. The Monadnock, the only one to take part in the Civil War, is usually considered the best of the U.S. monitors. In 1865/6 she went to San Francisco, via the Strait of Magellan and although three ships were in company, she was not towed.

Miantonomoh crossed the Atlantic in 1866, though she was towed for 1,100 miles by the side-wheel steamer Augusta. She returned in 1867 after a cruise of 17,767 miles. Two other ships, the Agamenticus and the Tonawanda were renamed Terror and Amphitrite respectively, on 15 June 1869.

The hull was of normal form without the Ericsson overhang, and freeboard is given as 2 feet 7 inches. The armour was made up of 1 inch plates and there were pilothouses on both turrets, with armored bases to the funnel and a large ventilation shaft abaft it. The turrets were 23 feet internal diameter and thus 2 feet larger than in the Passaic class, and a light hurricane deck was rigged between them.

Unfortunately the wooden hulls decayed and the supposed rebuilding of this class of vessels into the iron-hulled "New Navy" monitors of the same names, was a fiction to explain Congressional refusal to allocate any funds for new construction.

See also

for the new constructed monitors of the "New Navy".


  • Gardiner, Robert (1979). Conway's All The World's Fighting Ships 1860-1905. Conway Maritime Press. pp. p. 121. ISBN 0 85177 133 5.