Floating armouries are vessels used to store military grade weapons. Being in possession of military-grade weapons in most jurisdictions is highly controlled. In the early twenty-first century, piracy in international waters became a serious issue for shipping companies. In response, services that supply weapons on the high seas, often referred to as floating armouries, were implemented. These armouries provide transfer services to private maritime security companies (PMSCs); the controlled weapons are available in international waters, but never enter patrolled territorial waters—they are delivered by an armoury to a client's vessel, and returned, in international waters.