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.
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 Ynys Môn before the Boudican Rebellion.
[1] This suggests the force was still occupied in the Channel area, unsuitable to the long voyage up to the north of Wales, or too small by then to offer any useful level of support to the ground troops.
[4] The largest of these is at Beauport Park, near Battle, East Sussex, where more than 1000 tiles were used to roof a substantial bath house adjacent to a large iron smelting site.
[citation needed] Portus Adurni (which was later adapted and known as Portchester Castle) at the north of Portsmouth harbour is another contender and believed to have been at the very least a major base for the fleet.