The roots of the Coast Guard lie in the United States Revenue Cutter Service established by Alexander Hamilton under the Department of the Treasury on August 4, 1790. The first USCG station was in Newburyport, Massachusetts. Until the re-establishment of the United States Navy in 1798, the Revenue Cutter Service was the only naval force of the early U.S. It was established to collect taxes from a brand new nation of patriot smugglers. When the officers were out at sea, they were told to crack down on piracy; while they were at it, they might as well rescue anyone in distress.
"First Fleet" is a term occasionally used as an informal reference to the US Coast Guard, although as far as one can detect the United States has never in fact officially used this designation with reference either to the Coast Guard or any element of the US Navy. The informal appellation honors the fact that between 1790 and 1798, there was no United States Navy and the cutters which were the predecessor of the US Coast Guard were the only warships protecting the coast, trade, and maritime interests of the new republic.