50 Day Trail of a YANKEE Class Soviet SSBN by the USS BATFISH (SSN 681)
Following quotes from the now declassified USS BATFISH Patrol Report: MISSION LS-26
Mission LS-26 trailed a Soviet YANKEE Class SSBN from 17 March to 5 May 1978 during an entire Atlantic missile patrol cycle, a period of 50 consecutive days in contact. The mission was assigned the unclassified designation Operation EVENING STAR.
Initial intercept was made on 17 March in the Norwegian Sea at 70N latitude. Following loss of contact late on 19 March in a severe storm, LS-26 held intermittent contact on the YANKEE throughout the day of 20 March. Firm contact was re-established late on 21 March with the assistance of U.S. VP ASW aircraft in the Iceland-Faeroe Gap.
The YANKEE was trailed continuously for 44 full days until the mission was terminated at the direction of CTG 84.10 in the Norwegian Sea north of the Arctic circle on 5 May 1978.
During the trail period, the YANKEE traveled 8,871 measured track miles while LS-26 steamed 10,369 miles positioning to maintain tactical control.
The YANKEE transited to the WESTLANT patrol area at speeds of 9 to 11 knots making good an SOA of 8.5 knots. Baffle clears were observed every one to two hours, and were frequently accompanied by the use of BLOCKS OF WOOD Sonar. Probable bottom contour navigation operations were also observed. Periscope depth operations were noted twice daily.
After crossing the Mid-Atlantic Ridge just north of the Azores, the YANKEE assumed an alert patrol status at 022100Z April 1978, within SS-N-6 missile range of the U.S. East Coast (1600 nm). During the 19-day alert patrol phase, the YANKEE used speeds of 6 to 7 knots to make good a 4 knot SOA. The length and complexity of baffle clears increased slightly. Periscope depth operations, including ventilation, were conducted once daily during hours of darkness.
The return transit to the Norwegian Sea enroute to the Soviet Northern Fleet was conducted through the Faeroe-Shetland Gap. A more relaxed posture was evident as the YANKEE executed fewer baffle clears and rarely used BLOCKS OF WOOD Sonar.