Operation Military_operation Rimau was an attack Attack on Japanese shipping in Singapore Harbour , carried out Action by an Allied commando unit Z Special Unit , during World War II using Australian built Building Hoehn military MKIII folboats .

Originally part of a much larger operation called Name_conferral `` Operation Hornbill '' , the aim Aiming of Rimau was to sink Removing Japanese shipping Self_motion by paddling Self_motion the folboats in the dark and placing Placing limpet mines on ships .

It was originally intended that motorised semi-submersible canoes , known as `` Sleeping Beauties '' , would be used Using to gain Getting access Having_or_lacking_access to the harbour , however , they resorted to folboats .