Building the "90-day" Gunboats

Unadilla, Winona, and Ottawa under construction

As part of its emergency building program to put ships on the blockade, the U.S. Navy designed a shallow draft, steam-powered gunboat that could be easily assembled. Labelled the "90-day" gunboats as the contract stipulated that the private shipyards had to complete the construct of the vessels in ninety days, these warships became a mainstay of blockading squadrons. While none of them were completed in the allotted time, the program still demonstrated the Union's tremendous industrial advantage over the South as the program cranked out twenty-three good warships in five months. 

William  Henry Webb (left) and Jacob Aaron Westervelt (right)

Four of New York City's most prominent shipbuilders, John Englis, William H. Webb, Jacob Aaron Westervelt (Westervelt & Company), and Cornelius Poillon (Bridge Street Yard) are credited with the remarkable success of the project as they built the ships in an almost assembly like fashion.

Finished "90-day" gunboats

Each ships was 158 ft. long, had a 28 ft. beam, displaced about 560 tons, and only drew 10 feet of water. Despite their small size, the Navy armed the ships with several Dahlgren boat howitzers, a few older cannons, and one IX-inch or XI-inch Dahlgren smoothbore.  One sailor reported that when the main gun was fired, it "would shake the whole ship." Despite their hasty construction, the ships would serve in every blockading squadron and every major littoral campaign.  Many of the ships would serve in the Navy after the war.