Vessels: U

U.S. COAST GUARD VESSELS

* Hermes

U.S. COAST SURVEY VESSELS

* Active

* Catalina (sloop)

* Ewing

* Hassler

* McArthur

* Olympia

U.S. LIGHTHOUSE SERVICE TENDERS

* Madroño (tender)

* Sequoia

* Shubrick

• U.S.S. Burrfish (San Clemente Island shipwreck 1969)
• U.S.S. Cabildo (San Nicolas Island shipwreck 1985)
• U.S.S. Moray (San Clemente Island shipwreck 1970)
• U.S.S. Ulvert M. More (San Nicolas Island shipwreck 1966)
• Umatilla
• Uncontrollable Urge (San Clemente Island shipwreck 2013)
• Undine (Santa Cruz Island shipwreck 1890)
• Unity (Santa Cruz Island shipwreck 1922)
• Unome

U.S. REVENUE CUTTERS [morphed to become U.S. Coast Guard in 1915]

* U.S. Revenue Cutter Bear (1902) San Nicolas Island, Santa Catalina Island

* U.S. Revenue Cutter McCulloch (1901) Channel Islands

* U.S. Revenue Cutter Thomas Corwin (1897) Channel Islands

* U.S. Revenue Cutter Daniel Manning (1904; 1908) Channel Islands, San Miguel Island

* U.S. Revenue Cutter Wolcott (1894) San Clemente Island

* U.S. Wayanda (1870s) Farallon Islands

U.S. AIRSHIPS

* U.S.S. Macon (dirigible]

U.S. WAR SHIPS

* U.S.S. Koka (tug; San Clemente Island postal covers - 1935; broke up at San Clemente Island in 1937)

* U.S.S. Day (scuttled at San Clemente Island)

* U.S.S. Portland (San Clemente Island postal covers - 1933 & 1934)

* U.S.S. Ranger (first aircraft carrier; San Clemente Island postal covers - 1937 & 1938)