 Lithograph of a Unadilla-class gunboat, ca. 1861
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| Class overview | |
|---|---|
| Name | Unadilla or "90-day" class |
| Builders | See table |
| Operators | U.S. Navy |
| Cost | $90,000–$103,500 |
| Built | 1861–62 |
| In service | 1861–1885? |
| In commission | 30 Sep 1861–18 Sep 1869 |
| Completed | 23 |
| Active | None |
| General characteristics | |
| Class and type | Unadilla-class gunboat |
| Displacement | 691 tons |
| Tons burthen | 507 |
| Length | 158 ft (48 m) (waterline) |
| Beam | 28 ft (8.5 m) |
| Draft | 9 ft 6 in (2.90 m) (max.) |
| Depth of hold | 12 ft (3.7 m) |
| Propulsion | 2 × 200 IHP 30-in bore by 18 in stroke horizontal back-acting engines; single screw |
| Sail plan | Two-masted schooner |
| Speed | 10 kn (11.5 mph) |
| Complement | 114 |
| Armament |
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The Unadilla class was a class of gunboat built for the Union Navy at the outbreak of the American Civil War. Ships of the class were also known as "90-day gunboats" due to their rapid construction. The class was designed to be fully oceangoing while having a light enough draft to be able to operate close inshore, for blockade duty or other operations in shallow waters.
Unadilla-class gunboats took part in many coastal and river operations, most notably as the bulk of the fleet which captured the vital Confederate port of New Orleans in April 1862. As blockade ships, the 23 vessels of the class captured or destroyed no fewer than 146 enemy blockade runners during the war— about 10 percent of the total number of Confederate blockade runners so neutralized.
The Unadilla class was sold off quickly by the Navy at the end of the war, most of them going into merchant service. Little is known about their subsequent careers.