North Sea Signal Stations

In the later Empire the signal station undergoes the same architectural development as the castellum. It grows larger and stronger, more massive in construction and more defensible in character.

A series of Roman signal stations, established in the fourth century AD,  are situated on promontories of the North Yorkshire coast at roughly even intervals, stretching from Huntcliff to Filey, a distance of almost 60 kilometres. The stations formed a chain of fortified watchtowers, strategically positioned to observe the North Sea and the exposed Yorkshire coast. Their close similarities in plan and closely dated occupation levels suggests their conception and construction as a single defensive work, each ineffective as an isolated structure, but together acting as an efficient surveillance network.

They are protected not by a palisade, but by a stone wall, enclosing the fortlet and entered by one gateway and defended by a bastion at each angle; outside this is a ditch, separated from the wall by a wide berm. The design is described in an inscription from Ravenscar as 'turrem et castrum'.

Their function was to look out to sea for pirate raiders and to signal to fortified fleet stations along the coasr, whence ships could the enemy before they landed, or keep in touch with thier movements.

Camouflaged scout ships are described by Vegetius.

Locations of North Sea Signal Stationss in Roman Britain