in cuiiKjai, me u.a. /in neeiseemed to be playing an increasing role. A spokesman reported two destroyers, Stoddard and Ingersoll, lobbed explosives into Communist shore positions Thursday.The Stoddard, assigned to defend the Da Nang harbor, was credited with “very effective harassment and interdiction fire” in a 249-shell bombardment of enemy positions. Spotters estimated the Ingersoll killed seven Vietcong and wounded 15 in a strike 120 miles south of Da Nang.FLIERS struck hard again at Communist targets on both sides of the border. A military spokesman announced a half dozen bombing missions against North Vietnam. He said U.S. Air Force and Vietnamese war planes flew 165 sorties against Vietcong concentrations and facilities in the south. A sortie is the flight of one plane.The spokesman said an American pilot and his Vietnamese observer were killed in the crash of a U.S. Air Force observation plane that was directing a strike 50 miles south of the Da Nang air base. Field observers reported the plane pulled up, stalled and fell after pinpointing a target with smoke.A mishap in the Da Nangarea cost the life of a U.S. ow- 'Marine.THE SPOKESMAN said the Marine, who had been investigating suspicious noises, was shot dead before dawn when he failed to answer a sentry’s challenge.