A Coast Guard Officer is a member of the United States Coast Guard, a branch of the United States Armed Forces. The most common ranks for a Coast Guard Officer are ENSIGN (ENS), ENSIGN (ENSIGN), SPAR, SONAR, and CUTTER. An ENSIGN is the lowest rank of commissioned officer in the Coast Guard, while an ENSIGN is the most junior commissioned officer rank. A SPAR is a Petty Officer First Class, a SONAR is a Petty Officer Second Class, and a CUTTER is a Chief Petty Officer. All of these ranks are responsible for the safety and security of the United States' coasts and waterways.