 Originally part of a much larger operation called "Operation Hornbill", the aim of Rimau was to sink Japanese shipping by paddling the folboats in the dark and placing limpet mines on ships.It was originally intended that motorised semi-submersible canoes, known as "Sleeping Beauties", would be used to gain access to the harbour, however, they resorted to folboats.After the raiding party's discovery by local Malay authorities, a total of thirteen men (including raid commander Lyon) were killed during battles with the Japanese military at a number of island locations or were captured and died of their wounds in Japanese captivity.