April 16, 1969 – February 26, 1970. Operation Market Time.

Between 20 September 1966 and 15 February 1967, Mine Squadron Eleven Detachment Alfa suffered eleven members killed in action and two classified as missing in action. In 1968, Detachment Alfa became Mine Division 112, and a new sister division, Mine Division 113, was formed. Between 16 April 1969 and 26 February 1970, this small combined mine force, comprised almost entirely of enlisted, lost another four sailors. Collectively, the two divisions sustained almost all the casualties suffered onboard mine warfare vessels in Vietnam. While relatively few sweep sailors worked inshore in South Vietnam, at any given time hundreds were serving off shore aboard ocean and coastal minesweepers engaged in Operation Market Time. This operation involved the boarding and searching of thousands of junks, sampans and fishing boats in an effort to prevent or reduce seaborne North Vietnamese infiltration of men, munitions, and supplies into South Vietnam. Sweep sailors also comprised the crews of the minesweeping launches carried aboard USS Epping Forest (MCS-7) and, later, USS Ozark (MCS-2). These mine countermeasures support ships served as flagship of Commander, Mine Flotilla One, based in Sasebo, Japan. The launches swept harbors and inlets too shallow for minesweepers. [198]