Classis Britannica

The Classis Britannica (literally, British fleet, in the sense of 'the fleet in British waters' or 'the fleet of the province of Britannia', rather than 'the fleet of the state of Britain') was a provincial naval fleet of the navy of ancient Rome. Its purpose was to control the English Channel and the waters around the Roman province of Britannia. Unlike modern (and some contemporary Roman) "fighting navies", its job was largely the logistical movement of personnel and support, and keeping open communication routes across the Channel.

There is no literary reference in the classical historians to the Classis Britannica by that name, and archaeological evidence is also tantalizingly scant (although tiles stamped CLBR are common along the east Kent coast and in London, suggesting either government buildings or an early instance of army surplus), meaning that details of its history and form are unfortunately based on a large degree of interpretation.

A fleet was originally raised for the invasion of Britain under Claudius, with the task of bringing an invasion force of 40,000 men from the Roman army, plus supplies, to Great Britain. It continued after the successful invasion to provide support for the army, shuttling massive quantities of supplies across the English Channel.

This fleet played a major role in the subsequent conquest of Britannia. However, Tacitus states that strangely, about twenty years after the invasion, it was not present at Suetonius Paulinus's crossing of the Menai Strait to Anglesey before the Boudican Rebellion. This suggests the force was still occupied in the Channel area, unsuitable to the long voyage up to north Wales, or too small by then to offer any useful level of support to the ground troops.

In the Flavian period what had been raised initially as a temporary invasion fleet was formalised as the Classis Britannica and made permanent in statute. Also in the Flavian period, under the governor Agricola, it circumnavigated Caledonia (Scotland), and in 83 attacked its eastern coast. One year later the fleet is recorded as having reached the Orkney Islands.

...
Wikipedia