" Quentin leaned forward. A circle had just changed to a dot. A P-3C had just dropped an explosive sounding charge and localized an Echo-class attack sub five hundred miles south of the Grand Banks. For an hour they had a near-certain shooting solution on that Echo; her name was written on the Orion’s Mark 46 ASW torpedoes. "

― Tom Clancy , The Hunt for Red October (Jack Ryan, #3)