Following unclassified:

Trail was established on 12 May 1972 sixty miles north of Tsushima Straights. The ECHO II (PAPA 07) continued southward transiting between Duke Shima and Shima, Meshima Islands. Upon entering th Philippine Sea, the ECHO II set a course direct for the BASHI Channel into the South China Sea.

On 26 May, PAPA 07 departed the South China Sea holding area and transited to a holding area in the Philippine Sea about 100-150 nm south-southeast of Sakishima Gunto.

PAPA 07 transited at an estimated depth of 200-260 feet at 270-340 rpm and cleared baffles religiously on the hour. He usually did housekeeping routines while at periscope depth. Frequently, bottles were heard imploding as he ejected garbage, indicating a disregard for self-noise while transiting. Optimum trail range was 6-8,000 yards.

The ECHO usually increased speed to 270 rpm on one screw during pericope depth excursions and cavitated while shallow. At 060527Z June, the ECHO increased speed to 368 rpm on course 250. At 060550Z, contact was lost. Subsequent search down his track was unsuccessful and a lost contact SITREP was transmitted. At 062330Z, received CTG 70.9 message terminating the operation and directing our transit to Guam.