The U.S. Navy <i>Aggressive</i>-class minesweepers USS <i>Skill</i> (MSO-471), USS <i>Nimble</i> (MSO-459), USS <i>Pinnacle</i> (MSO-462) and USS <i>Sagacity</i> (MSO-469), circa 1960.
USN
<a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/department_arch.html">U.S. Navy All Hands magazine</a> <a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/archpdf/ah196004.pdf">April 1960</a>, p. 29.