In response, the United States Air Force and U.S. Navy launched Operation Linebacker, a major bombing offensive against North Vietnam.

[2][3][4] Eventually, North Vietnam and the United States negotiated an end to the war and signed the Paris Peace Accords on 27 January 1973.

A protocol to the agreement called for the United States to neutralize American mines in North Vietnam's coastal and inland waterways.

[6] In the United States, the Chief of Naval Materiel, Admiral Isaac C. Kidd, Jr., organized a Mine Warfare Program Office charged with controlling scientific and technical support to End Sweep.

[7] Ten ocean minesweepers (MSOs) were assigned to Task Force 78 to sweep deep-water approaches to North Vietnamese ports and inland waterways and to serve as helicopter control vessels.

In addition, the tank landing ship USS Washtenaw County (LST-1166) was modified in Japan between November 1972 and February 1973 to serve in End Sweep as a "special device minesweeper," redesignated MSS-2.

She was pumped full of polyurethane foam so that she would not sink if she struck a mine, was equipped with padding to protect her all-volunteer skeleton crew, and was modified so that her entire crew of six could remain topside during her minesweeping runs, ensuring that they would be blown overboard if she struck a mine rather than injured or killed by slamming into the overhead anywhere below decks.

As a result, a scientist devised a buoyant, magnetized pipe filled with styrofoam which any helicopter pilot could tow easily.

The talks broke down in December 1972, however, so the task force awaited further developments into January 1973 while its helicopter crews practiced towing their minesweeping equipment in Subic Bay.

The next day, however, President Nixon ordered a suspension of End Sweep in response to North Vietnamese delays in releasing prisoners-of-war.

[4] Although End Sweep was a great success in the eyes of the American leadership and general public, U.S. Navy mine warfare analysts were less sanguine about what the operation had demonstrated.

[12] The American public and many U.S. Navy personnel came away from End Sweep with the impression that helicopters had replaced surface ships in the minesweeping role due to their effectiveness and far greater mobility.