In May 1967 as part of Task Force 77, "Forrest Royal" took part in Operation Sea Dragon. Although air power was the cutting edge of Task Force 77, surface ships were essential to the interdiction campaign in North Vietnam and Laos. In Operation Sea Dragon, begun in October 1966, cruisers, destroyers, and for one month battleship ranged the North Vietnamese littoral sinking Communist supply craft, shelling coastal batteries and radar sites, and complementing the aerial interdiction effort by bombarding the infiltration routes ashore. While at first restricted to coastal waters south of 17°31'N, by February 1967 the Sea Dragon force was authorized to operate as far north as the 20th parallel. This area was constricted in April 1968 when the bombing halt ended American combat activity north of the 19th parallel.