Offshore and nearby, are concrete and brick relics of "Indicator Loop &amp; Controlled Mining Station number 285", constructed by the Royal Australian Navy during world war two. Mines were laid in this area. An indicator loop was an electrically charged cable, used to indicate shipping movements. In this case, the cable was situated from Hungry Beach to Juno Point at Patonga, two kilometres distant on the opposite side of the Hawkesbury River. The cable was used in the detection of Japanese submarines and to protect the railway bridge. An infra red photo electric beam shone 2.6 kilometres from Hungry Point to the Central Coast, in order to detect enemy shipping.