In 1963 Deacock went to Heard Island as a member of the Australian National Antarctic Research Expeditions. During the expedition, there was an attempt on climbing Big Ben to investigate glaciology, geology and volcanology of the unexplored area. Due to a prolonged blizzard and a lost food depot, the attempt was abandoned. One of the three members (Grahame Budd) had frostbitten hands but all survived. The three had lost their tent, sleeping bags and other equipment.