USS SC-27, during her service life known as USS Submarine Chaser No. 27 or USS S.C. 27, was an SC-1-class submarine chaser built for the United States Navy during World War I. She later served in the United States Coast Guard as USCGC Richards.

SC-27 was a wooden-hulled 110-foot (34 m) submarine chaser built at the New York Navy Yard at Brooklyn, New York. She was commissioned on 8 November 1917 as USS Submarine Chaser No. 27, abbreviated at the time as USS S.C. 27.

Submarine Chaser No. 27 was transferred to the U.S. Coast Guard on 13^[3] or 14^[5] November 1919 at Norfolk, Virginia.

The U.S. Navy adopted its modern hull number system on 17 July 1920, after Submarine Chaser No. 27 had left Navy service. Had she remained in Navy service at that date, she would have been classified as SC-27 and her name would have been shortened to USS SC-27, and she now is referred to retrospectively by this name.

The Coast Guard commissioned the submarine chaser as USCGC Richards. As of 1 January 1923 she was based at South Baltimore, Maryland.

The Coast Guard found Richards, like other SC-1-class submarine chasers, too expensive to operate and maintain, and sold her on 29 January 1923.

•  This article incorporates text from the public domain Dictionary of American Naval Fighting Ships. The entry can be found here.
• NavSource Online: Submarine Chaser Photo Archive: USCGC Richards ex-USS SC-27
• The Subchaser Archives: The History of U.S. Submarine Chasers in the Great War Hull number: SC-27
• United States Coast Guard Historian's Office: Cutters and Craft: Richards, 1919 ex-SC-27
• Woofenden, Todd A. Hunters of the Steel Sharks: The Submarine Chasers of World War I. Bowdoinham, Maine: Signal Light Books, 2006. ISBN 978-0-9789192-0-7.