This was the British destruction of the Japanese heavy cruiser Takao in Singapore harbour by midget submarine attack (30/31 July 1945).
During February 1945 the depot ship Bonaventure departed England for the Pacific with six improved ‘XE’ class midget submarines, and in July reached Brunei Bay. The British naval command in the Far East could initially see no use for such craft in the Pacific, and the decision was therefore made to scrap them and turn the depot ship over to the Pacific Fleet’s fleet train. Then there emerged the concept of cutting the cable providing a communications link between the Japanese headquarters in Singapore, Saigon and Hong Kong, and when Bonaventure’s captain pointed out that his ‘XE’ craft were well suited to any such enterprise, the midget submarines were at once reprieved for 'Foil' and 'Sabre'.
In addition to the cable-cutting operation the boats were given the task of destroying the heavy cruisers Takao and Myoko, which were in Singapore and, although damaged, might be repaired sufficiently to molest the forces which Admiral the Lord Louis Mountbatten’s South-East Asia Command was assembling for the ‘Zipper’ invasion of Malaya.
On 26 July the submarines Spark and Stygian accordingly departed Brunei for Singapore with XE-1 (Lieutenant J. E. Smart) and XE-3 (Lieutenant I. E. Fraser) in tow. Four days later the parent submarines slipped the midget boats at the eastern entrance to the Singapore Strait after dark and withdrew to a rendezvous farther out to sea.
XE-3 then safely negotiated the 40-mile (65-km) passage to the naval base in Johore Strait, but found Takao lying in water so shallow that there was barely room to manoeuvre below her. It was with the greatest difficulty that the diver in the crew, Leading Seaman J. J. Magennis, placed the limpet mines carried on one side of the midget submarine, but finally managed the task. Fraser then released the explosive charge carried on the midget submarine’s port side. When he tried to withdraw, however, he found that his craft was jammed between the cruiser’s hull and the bottom. After a hectic struggle he extricated his vessel, but broke surface in doing so and was fortunate not to be sighted. XE-3 then submerged once more, and finally made the rendezvous with Stygian.
Meanwhile XE-1, which should have been ahead of Fraser’s craft, had been delayed by the activities of Japanese patrol vessels, and Smart realised that he could not reach Myoko, which was lying 2 miles (3.25 km) farther up the strait, and complete his attack before the XE-3’s charges were due to explode. Smart therefore decided to switch to Takao, successfully placed his charges as close to her as he could get, and then withdrew to his rendezvous with Spark.
The double attack by the two ‘XE’ craft damaged the Japanese cruiser severely, and she sank onto the sea bed. The two midget submarines and their parent submarines all reached Brunei Bay safely on 4 August.
Meanwhile Spearhead had towed XE-4 from Brunei Bay to a position off Saigon, where the tow was slipped on the evening of 30 July. On the next day the midget submarine’s crew successfully located and cut the cables in 'Sabre'. Lastly Selene with XE-5 in tow left Subic Bay on 27 July and spent three and a half days searching for the cables in deep mud off Hong Kong in 'Foil'. Though her skipper was not certain that he had succeeded in his purpose, it was discovered after the war’s end that he had in fact put the cable out of action.