Military vessels are ships and submarines used by a nation's armed forces to conduct naval operations. They are designed for various purposes, including combat, surveillance, and transportation of troops and equipment. Common types of military vessels include aircraft carriers, destroyers, frigates, and submarines, each serving specific roles in naval warfare. These vessels are equipped with advanced technology and weaponry to protect national interests and maintain maritime security. They can operate independently or as part of a larger fleet, often collaborating with other military branches and allied forces during joint operations.