Operation Rimau was an attack on Japanese shipping in Singapore Harbour, carried out by an Allied commando unit Z Special Unit, during World War II using Australian built Hoehn military MKIII folboats. It was a follow-up to the successful Operation Jaywick which had taken place in September 1943, and was again led by Lieutenant Colonel Ivan Lyon of the Gordon Highlanders, an infantry regiment of the British Army. 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. A group of ten commandos were transported to Outram Road Jail in Singapore after capture by the Japanese, were tried with perfidy and espionage in a Japanese court and executed on 7 July 1945. Planning After the success of the earlier Operation Jaywick mission in September 1943, Ivan Lyon started preparing for Operation Rimau. 'Rimau' is the Malay word for 'tiger' and Lyon had a large multi-coloured tiger head tattooed on his chest. The mission consisted of 23 men with an additional two performing the duties of "conducting officers". The plan was to: deliver commandoes to enemy waters via submarine with 15 one-man, motorised submersible canoes known as "Sleeping Beauties" (SBs) (these could be used on the surface or travel semi-submerged, with the operator's head above the water or fully submerged similar to a small submarine, the operator using artificial breathing apparatus similar to modern Scuba diving equipment); travel to the uninhabited Merapas Island in Indonesia which they would use as a base and place enough supplies for three months; have the commandoes capture a small local fishing boat; sail the boat towards Singapore Harbour undetected, disguising the commandos as locals; reach the Bay of Kepala Jernih (in the Tambelan Archipelago) late on 9 October 1944 for 24 hours to allow an officer to carry out a reconnaissance from Pulau Subar ("Sisters' Islands"); the officer was to spend the time observing