The Stop Our Ship (SOS) movement, a component of the overall civilian and GI movements against the Vietnam War, was directed towards and developed on board U.S. Navy ships, particularly aircraft carriers heading to Southeast Asia. It was concentrated on and around major U.S. Naval stations and ships on the West Coast from mid-1970 to the end of the Vietnam War in 1975, and at its height involved tens of thousands of antiwar civilians, military personnel and veterans. It was sparked by the tactical shift of U.S. combat operations in Southeast Asia from the ground to the air. As the ground war stalemated and Army grunts increasingly refused to fight or resisted the war in various other ways, the U.S. “turned increasingly to air bombardment”. By 1972 there were twice as many Seventh Fleet aircraft carriers in the Gulf of Tonkin as previously and the antiwar movement, which was at its height in the U.S. and worldwide, became a significant factor in the Navy. While no ships were actually prevented from returning to war, the campaigns, combined with the broad antiwar and rebellious sentiment of the times, stirred up substantial difficulties for the Navy, including active duty sailors refusing to sail with their ships, circulating petitions and antiwar propaganda on board, disobeying orders, and committing sabotage, as well as persistent civilian antiwar activity in support of dissident sailors. Several ship combat missions were postponed or altered and one ship was delayed by a combination of a civilian blockade and crewmen jumping overboard. The major targets of the SOS movement were four different aircraft carriers, the USS Constellation, the USS Coral Sea, the USS Kitty Hawk and the USS Enterprise, with lesser but significant activity on and around a number of other ships. USS Constellation The first effort began in 1970 in San Diego, the principal homeport of the U.S. Navy's Pacific Fleet. A San Diego-based antiwar group, Nonviolent Action, founded by peace activist Francesco Da Vinci, came up with the idea of the Constellation Project, sometimes called The Harbor Project (the SOS name developed later). It was a nonviolent campaign to oppose the war and, at the same time, to show support for the crew of the USS Constellation. Through leaflets and letters, NVA told the sailors that they were not against them, they were only against their orders. NVA's nonviolent campaign attracted other peace groups such as the Concerned