It was as a 19 year old Corporal in the North Australia Observer Unit in the Northern Territory in 1942 that Theo Carty's concern for the security of Northern Australia was first aroused. He spent hours with Mr Herbert of Koolpinyah Station learning the habits of the mighty Adelaide River during the wet season, noting the ease with which craft could arrive along the coast and be carried inland by the prevailing winds and tidal flow. Carty later reflected that Herbert had shared his fears of a silent invasion.
