Abstract: A sonobuoy for launching at high altitudes from present sonobuoy launching tubes. A plurality of spring loaded stabilizing fins are held in place adjacent the body of the sonobuoy by rotovanes in their stored position. Upon launching the sonobuoy from an aircraft, the stabilizing fins assume their stabilizing position substantially perpendicular to the body of the sonobuoy due to the spring action but are held in place by the stored rotovanes. Upon reaching a lower altitude, the rotovanes are released to allow rotochute action to slow the descent of the sonobuoy. Upon deployment of the rotovanes to their operating position, the stabilizing fins previously held in place by the stored rotovanes separate to allow proper rotochute action.