High Quality Content by WIKIPEDIA articles! Anti-frogman techniques are security methods developed to protect watercraft, ports and installations, and other sensitive resources both in or nearby vulnerable waterways from potential threats or intrusions by frogmen or other divers. In World War II this need for military underwater security was first shown by the achievements of frogmen against armed forces facilitie, see for example Italian frogman actions in WWII. Since the late 1950s, the increasing demand for and availability of sophisticated scuba diving equipment has also created concerns about protecting valuable underwater archaeology sites and shellfish fishing stocks. The 12 October 2000 USS Cole bombing was not carried out by underwater divers, but did bring renewed attention to the vulnerability they present for naval ships. Divers can swim 100 to 200 yards in three minutes time, and large sonar ranges would need to be established around ships in order for security forces to detect underwater swimmers in time to make a sufficient response.