USCGC Blackthorn collides with the tanker Capricorn while leaving Tampa, Florida and capsizes, killing 23 Coast Guard crewmembers.

USCGC Blackthorn (WLB-391) was a 180-foot (55 m) seagoing buoy tender (WLB) which sank in 1980 in a collision near the Tampa Bay Sunshine Skyway Bridge, resulting in 23 crew member fatalities. An Iris-class vessel, she was built by Marine Ironworks and Shipbuilding Corporation in Duluth, Minnesota. Blackthorn's preliminary design was completed by the United States Lighthouse Service and the final design was produced by Marine Iron and Shipbuilding Corporation in Duluth. On 21 May 1943 the keel was laid, she was launched on 20 July 1943 and commissioned on 27 March 1944. The original cost for the hull and machinery was $876,403.

Tampa is a city on the Gulf Coast of the U.S. state of Florida. Tampa's borders include the north shore of Tampa Bay and the east shore of Old Tampa Bay. It is the third-most populous city in Florida and 49th-most populous city in the country with a population of 403,364 at the 2020 census, while the Tampa Bay metropolitan area at over 3.42 million residents is the second-largest metropolitan area in Florida and 17th-largest in the United States. The Greater Tampa Bay area has over 4 million residents and generally includes the Tampa and Sarasota metro areas.