The USS Picket was a small Union gunboat that

Engraving labeled "The Burnside Expedition - Landing of the national troops on Roanoke Island, under cover of the Union gunboats Delaware and Picket." Image from Archive.org.
Engraving labeled "The Burnside Expedition - Landing of the national troops on Roanoke Island, under cover of the Union gunboats Delaware and Picket." Image from Archive.org.
fought during the Civil War in the sounds and rivers of North Carolina until September 1862, when it was sunk in the Tar River at Washington, N.C. The Union had purchased this civilian vessel for use in an expedition along the coast of North Carolina led by Maj. Gen. Ambrose E. Burnside. The exact origin of the Picket was obscured by the existence of a larger, side-wheel steamer of the same name that also served during the war. The two vessels are sometimes confused in existing records.

The smaller Picket was one of seven armed propellers accompanying the Burnside expedition when it sailed for North Carolina in January 1862. The ships were collected in haste and formed a motley fleet that inspired skepticism among Burnside's officers and men as to their seaworthiness. Therefore, to demonstrate his own confidence in the vessels, Burnside chose the Picket (the smallest ship in the fleet) as his flagship for the voyage. After the Burnside expedition began operations in North Carolina waters, the Picket, with its shallow draft, proved to be particularly valuable for covering the landing of Union troops at Roanoke Island, New Bern, and Fort Macon.

On the morning of 6 Sept. 1862, as the Picket lay with the navy gunboat Louisiana in the Tar River at Washington, N.C., a Confederate force made a surprise attack on the town. Both gunboats went into action to shell the advancing Confederates, but the Picket was able to fire only one gun before it exploded and sank in the river, killing its captain, Sylvester D. Nicoll, along with 18 crewmen and leaving 6 others wounded.

References:

John S. Carbone, The Civil War in Coastal North Carolina (2001).

Robert U. Johnson and Clarence C. Buel, eds., Battles and Leaders of the Civil War, vol. 1 (1887-88).

Additional Resources:

Simms, Scott. "Sinking of The Picket." The Sag Harbor Express. September 7, 2012.  http://sagharborexpress.com/sinking-of-the-picket/  (accessed October 11, 2012).

dcbh. "22 February 1862: Illustration, 'The ‘Picket’ leading the ships of the Burnside expedition over Hatteras Bar.'" The Civil War Day by Day (blog). Louis Wilson Round Special Collections Library, University of North Carolina at Chapel Hill. http://www.lib.unc.edu/blogs/civilwar/index.php/2012/02/22/22-february-1862-3/  (accessed October 11, 2012).

"Picket." Community Images Researchable by Computer Access NC East, George H. and Laura E. Brown Library; Beaufort County Community College. http://circanceast.beaufortccc.edu/Brown/Picket/picket.htm  (accessed October 11, 2012).

Gaines, W. Craig. "Picket (James E. Winslow) (Launch No. 5) (USS Picket) (Picket Boat No. 5)." Encyclopedia of Civil War Shipwrecks. Louisiana State University Press. 2008. http://books.google.com/books?id=90d2LcmfpCcC&lpg=PA225&ots=fd-VDLLaDX&dq=%22uss%20picket%22%20civil&pg=PA127#v=onepage&q&f=false  (accessed October 11, 2012).

Image Credits:

"The Burnside Expedition - Landing of the national troops on Roanoke Island, under cover of the Union gunboats Delaware and Picket." Frank Leslie's Illustrated Newspaper. March 8, 1862. p. 245. https://archive.org/stream/franklesliesilluv1314lesl#page/n239/mode/2up (accessed October 11, 2012).