Brown water navy
Brown water navy is a term in American naval jargon referring to actions in near shore and riverine environments. Small gunboats and patrol craft are the ships used by a brownwater force. World War II PT boats and the interwar river gunboats are forerunners of the concept. The littoral combat ship may have been brown-water capable, and Naval War College wargaming has shown the effectiveness of the idea. The term was used extensively for the riverine patrols used during the Vietnam War. Sen. John Kerry of Massachusetts made his service in the Vietnam era brownwater navy a center piece of his 2004 Presidential campaign.
"Brown water" is used to differentiate these ideas from the large, ocean-going "blue water" ships preferred by the Navy.