Cabled subsea observatories are becoming a common way of monitoring deep sea parameters on a long-term basis. Observatories typically comprise of a long distance high voltage power and data backbone cable onto which several instrumentation spurs are connected. Such systems provide scientists with a way of permanently and directly monitoring large areas of ocean in real-time. By their very nature such systems are scale large projects involving massive investment. Recently, the opportunity arose to establish a low-cost small-scale observatory in the tidal estuary of the river Ythan in Aberdeenshire, Scotland, near to Oceanlab. This paper describes the design and implementation of the system which comprises of a frame, located on the bed of the estuary, onto which are mounted a number of instruments. This is connected to the shore via 500m of combined fibre optic and copper cable.