Customs registers are the ultimate official source of data on British ships. Each ship has its own register, giving exact details of its size, build and owners. Two copies were kept, one may now be in the Public Record Office [address], and the other in a local record office.

Customs registers aim to record precise and up-to-date details of every British-registered ship. They cover ownership, dimensions, construction of hull and engines, master`s name [definition], and details of any mortgages taken out on the ship. To use Customs registers, it is useful to understand how and why they were kept.

Registration of British ships began because the Government wanted to know which ships were truly British. They might be needed in times of war. Registration also allowed the Government to regulate various aspects of shipping. For the owner, registration meant he could prove his ship was British, giving it privileges under the Navigation Act which restricted certain trades to British ships. It also meant the ship could expect some protection from the Royal Navy.

Registration of a ship involved the owners declaring details of themselves, their ship and its masters to an official in the ship`s home port, the registrar. The registrar gave the owner a certificate of registration, which was usually kept on board the ship. The registrar copied the details on to a register form kept in the port. These forms were numbered consecutively so the vessel could be identified by its port number, e.g. Glasgow No. 14 of 1872. A further copy of the certificate, called a transcript [definition], was sent to a central body.

The owner had to notify the registrar of any changes in the ship`s details. The registrar noted the changes on the certificate and the office copy. He also passed details to the central registration body on another form called a transaction [definition]. Users of Customs registers should be aware of the distinction between transcripts (simply copies) and transactions, which notified changes.

When ships were sold to an owner in another customs port, its registration was usually cancelled and the ship re-registered in the new port. The registrar wrote on the old certificate the date and reason it was `closed`, or cancelled. The port and port number of the new registration was usually added, making it is possible to trace a ship`s British career from one registration document to another. Registration was also closed when a vessel became a total loss, was hulked [definition], broken up, or sold abroad. Again, the reason was noted on the certificate.

Before 1889, ships were often re-registered at the same port if they were altered in some way, such as receiving a different rig [definition] or new machinery.

The name `Customs registers` came about because the officials who kept registration details in ports were usually customs officers, and the body to which copies of certificates were sent was originally the Customs House in London. Later, a Registrar General of Shipping and Seamen [ definition] was appointed to oversee registration and keep the records centrally.