Information:  - A sovereign state is, in international law, a nonphysical juridical entity that is represented by one centralised government that has sovereignty over a geographic area. International law defines sovereign states as having a permanent population, defined territory, one government, and the capacity to enter into relations with other sovereign states. It is also normally understood that a sovereign state is neither dependent on nor subjected to any other power or state.  - The Atlantic Ocean is the second largest of the world's oceans with a total area of about . It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the "Old World" from the "New World".  - The Archer class ( or P2000 ) is a class of patrol and training vessel in service with the United Kingdom 's Royal Navy , commonly referred to as a Fast Training Boat . Most are assigned to University Royal Naval Units , although HMS Tracker and HMS Raider are armed and provide maritime force protection to high value shipping in the Firth of Clyde although are most commonly employed as escorts for submarines transiting to Faslane .  - The North Sea is a marginal sea of the Atlantic Ocean located between Great Britain, Scandinavia, Germany, the Netherlands, Belgium, and France. An epeiric (or "shelf") sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than long and wide, with an area of around .  - The Irish Sea (, , , Ulster-Scots: "Airish Sea"), separates the islands of Ireland and Great Britain. It is connected to the Celtic Sea in the south by St George's Channel, and to the Inner Seas off the West Coast of Scotland in the north by the North Channel. Anglesey is the largest island within the Irish Sea, followed by the Isle of Man. The sea is occasionally, but rarely, referred to as the Manx Sea.  - Ireland, also described as the Republic of Ireland ('), is a sovereign state in north-western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, which is located on the eastern part of the island, and whose metropolitan area is home to around a third of the country's 4.75 million inhabitants. The state shares its only land border with Northern Ireland, a part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, Saint George's Channel to the south-east, and the Irish Sea to the east. It is a unitary, parliamentary republic. The legislature, the ', consists of a lower house, ', an upper house, ', and an elected President (') who serves as the largely ceremonial head of state, but with some important powers and duties. The head of government is the ' (Prime Minister, literally 'Chief', a title not used in English), who is elected by the Dáil and appointed by the President, and appoints other government ministers.  - The English Channel ("the Sleeve" [hence ] "Sea of Brittany" "British Sea"), also called simply the Channel, is the body of water that separates southern England from northern France, and joins the southern part of the North Sea to the rest of the Atlantic Ocean.  - Northern Ireland (; Ulster Scots: "") is a top-level constituent unit of the United Kingdom in the northeast of Ireland. It is variously described as a country, province, region, or "part" of the United Kingdom, amongst other terms. Northern Ireland shares a border to the south and west with the Republic of Ireland. In 2011, its population was 1,810,863, constituting about 30% of the island's total population and about 3% of the UK's population. Established by the Northern Ireland Act 1998 as part of the Good Friday Agreement, the Northern Ireland Assembly holds responsibility for a range of devolved policy matters, while other areas are reserved for the British government. Northern Ireland co-operates with the Republic of Ireland in some areas, and the Agreement granted the Republic the ability to "put forward views and proposals" with "determined efforts to resolve disagreements between the two governments".  - Ireland (Ulster-Scots: ) is an island in the North Atlantic. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the second-largest island of the British Isles, the third-largest in Europe, and the twentieth-largest on Earth.  - The European Union (EU) is a political and economic union of member states that are located primarily in Europe. It has an area of , and an estimated population of over 510 million. The EU has developed an internal single market through a standardised system of laws that apply in all member states. EU policies aim to ensure the free movement of people, goods, services, and capital within the internal market, enact legislation in justice and home affairs, and maintain common policies on trade, agriculture, fisheries, and regional development. Within the Schengen Area, passport controls have been abolished. A monetary union was established in 1999 and came into full force in 2002, and is composed of 19 EU member states which use the euro currency.  - Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, and the Mediterranean Sea to the south. To the east and southeast, Europe is generally considered as separated from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways of the Turkish Straits. Yet the non-oceanic borders of Europea concept dating back to classical antiquityare arbitrary. The primarily physiographic term "continent" as applied to Europe also incorporates cultural and political elements whose discontinuities are not always reflected by the continent's current overland boundaries.  - Great Britain, also known as Britain , is a large island in the north Atlantic Ocean off the northwest coast of continental Europe. With an area of , Great Britain is the largest European island and the ninth-largest in the world. In 2011 the island had a population of about 61 million people, making it the world's third-most populous island after Java in Indonesia and Honshu in Japan. The island of Ireland is situated to the west of it, and together these islands, along with over 1,000 smaller surrounding islands, comprise the British Isles archipelago.  - The Celtic Sea (; ) is the area of the Atlantic Ocean off the south coast of Ireland bounded to the east by Saint George's Channel; other limits include the Bristol Channel, the English Channel, and the Bay of Biscay, as well as adjacent portions of Wales, Cornwall, Devon, and Brittany. The southern and western boundaries are delimited by the continental shelf, which drops away sharply. The Isles of Scilly are an archipelago of small islands in the sea.  - The Kingdom of Great Britain, officially Great Britain , was a sovereign state in western Europe from 1 May 1707 to 31 December 1800. The state came into being following the Treaty of Union in 1706, ratified by the Acts of Union 1707, which united the kingdoms of England and Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands. It did not include Ireland, which remained a separate realm. The unitary state was governed by a single parliament and government that was based in Westminster. The former kingdoms had been in personal union since James VI, King of Scots, became King of England and King of Ireland in 1603 following the death of Queen Elizabeth I, bringing about a "Union of the Crowns". Also after the accession of George I to the throne of Great Britain in 1714, the kingdom was in a personal union with the Electorate of Hanover.  - A University Royal Naval Unit (URNU) is a Royal Navy training establishment connected to a university, or a number of universities concentrated in one area. There are 15 URNUs nationwide in the UK, and each URNU has land-based facilities near the university in question, up to four training officers (members of the Royal Naval Reserve) and, with the exception of Devon, a dedicated training vessel (an "Archer"-class P2000 fast patrol boat).  - The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by the English kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years War against the kingdom of France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is known as the Senior Service.  - The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another sovereign statethe Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world. The Irish Sea lies between Great Britain and Ireland. With an area of , the UK is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants. Together, this makes it the fourth most densely populated country in the European Union.    What entity does 'archer-class patrol vessel' has the relation 'subclass of' with?
The answer to this question is:
patrol boat