The origins of the Register General of all Trading Ships in Britain lay in the tightening of the administration of the Navigation Laws in the late seventeenth century, and the need to collect more detailed information about the movement of ships. The more modern series of these laws derived from a Commonwealth ordinance of 1651, as re-enacted at the Restoration. By then all plantation and coastwise trade was reserved, under stipulated penalties, to be imported in such English vessels or vessels of the country of origin, or usual place of shipment, of the goods. In 1701 one of the commissioners was directed to keep a register of all trading ships and to check the particulars of vessels engaged in outport shipping.
The office was placed on a more formal basis in 1707, when an article in the Act of Union directed that all Scottish ships should be 'entered in the General Register of all Trading ships belonging to Great Britain'. This register of British merchant ships embraced all ships whether registered in England, Scotland or the Plantations. In the larger ports registry of shipping business became sufficiently important to create a new type of record relating to registry matters.
The Act of General Registry 1786 required the official registry of every British vessel, whether built and owned at home or in the plantations, and in effect reregistry of every such vessel then afloat. This constituted a statutory registry, the source of 'states of navigation', accounts, tonnage statistics, and similar compilations.
In the office a record was filed of all ships engaged in the plantation trade, and to it were returned monthly accounts of all ships which entered as sailing coastwise and to or from a foreign port, with particulars as to cargo, tonnage, number of men, and whether British or foreign. Quarterly outport accounts of various commodities shipped coastwise and in or out were transmitted to it, and once a year two general accounts were returned, one containing the number of ships belonging to the port, with their tonnage and number of men, the other giving the number of British and foreign ships which had traded to and from the port during the year.
By an act of 1747 for the relief of distressed seamen and their dependants, masters of merchant ships were required to deposit muster rolls with the collectors of customs for each voyage. These contained names and addresses of the seamen, dates of engagement and discharge, and the names of their previous ships. These rolls were used until the Merchant Seamen's Fund Act 1851 made new arrangements for seamen's pensions.
From 1660 ships were registered by collectors of customs, but not until the early nineteenth century was a duplicate central register established. It was complete for United Kingdom ports by 1818 and for plantations by about 1820. By the Merchant Shipping Act 1854 a system of unique official numbers was introduced to replace the previous arrangement whereby ships were numbered at their port of registry.
On 4 January 1855 a Chief Registrar was appointed to take over from the Registrar General the central record of shipping. He had the duty of advising registrars throughout the United Kingdom and the colonies of the details of the new regulations and for ensuring uniformity of practice. All registrars had to forward to him from time to time full particulars of the registration of vessels. These details were recorded in his central register and he then allotted the official numbers which were to be appropriated to ships at all ports of the empire.
At the same time the statistical work of the Registrar General was transferred to the Registrar General of Seamen under the Board of Trade, who for this purpose held the duplicate registers. In 1856 the office of Chief Registrar was united with that of collector of customs in the Port of London. As a result of the Merchant Shipping Act 1872 the central register kept by the Chief Registrar of Shipping was discontinued and the sole responsibility for keeping such a register rested thereafter with the Registrar General of Seamen.
From 1 January 1873 he also took over the duty of allocating official numbers and was renamed the Registrar General of Shipping and Seamen, though the work of registration in the ports remained with the customs officials there. The Merchant Shipping Act 1894 laid down which officers should be registrars in ports in the United Kingdom, Channel Islands and colonies.
In the United Kingdom the Commissioners of Customs were to approve ports of registry and the chief officer of customs in each port was to be the registrar. All registrars were to transmit to the Registrar General of Shipping and Seamen full returns of dealings with ships on the register and, twice a year, a list of all ships registered, transferred or cancelled at the port.