September 24th 1941, the Dutch navy contacted the British Admiralty with the request to take over three new British T-class submarines. The Royal Dutch Navy had lost Hr. Ms. O 8 and Hr. Ms. O 12, due to the fact that they fell into the hands of the Germans on the14th of May 1940. Furthermore the navy would like Hr. Ms. K VII and the three boats of the K VIII-class to be removed from the fleet and in order to provide the available crew the opportunity to perform their war tasks, new submarines were required. At that time, the Royal Navy could not do without the T-class submarines, but did offer two smaller, but modern, U-class submarines to the Dutch navy.
On October 8th 1942, the first of these U-class submarines, the former P 47 was transferred into the service of the Dutch navy, as Hr. Ms. Dolfyn, at Holy Loch, Scotland. The former P 66 was to follow soon and would be named Haai, however the order had to be cancelled because the majority of the crew, intended for this boat, had been killed. In Australia, in the summer of 1942, the crew was assembled from the remaining crew of Hr. Ms. K IX, Hr. Ms. K X and Hr. Ms. K XII, under the command of Lieutenant Commander HCJ Coumou. In August 1942, the crew left from Sydney to Britain with the steamer Westernland of the Holland America Line. In Cape Town, South Africa, the ship had to be disembarked because it was judged not to be fit for the task of the use as a troopship. Consequently the Dutch submarine crew had to change over to the modern British motor vessel Abosso of the Elder Dempster Line. However, this ship would not join a convoy to sail to Britain, but it sailed as so-called independer. In the evening of October 29th 1942, 20 days after leaving Cape Town, the Abosso got torpedoed by the German submarine U-575, in the middle of the Atlantic Ocean. From the 33 future crew members of the Haai, 28 lost their lives. Subsequently, in 1944, Great Britain transferred the P 66 to the Norwegian navy, who took the ship into service as Ula.
In June 1943, Hr. Ms. O 14 was put out of service due to serious technical defects. Thus a complete, trained submarine crew became available. The Royal Dutch Navy got HMS Sturgeon to their disposal, a British S-class submarine. In contrast to the Dolfyn, this boat was not purchased, but obtained in lend-lease and taken into Dutch service as Hr. Ms Zeehond on the 18th of October 1943. With this submarine, the crew continued the task of Hr. Ms. O 14 produced as an ASDIC training boat.
In 1943, the Dutch request to take over T-class submarines could partly be honoured. In that year, the Dutch navy could take over the Talent, which then was still under construction and which was taken into service on the 23rd of November, 1943, as Hr. Ms. Zwaardvisch. This T-class submarine, in Dutch service, was to carry out one of the most successful allied patrols during the Second World War. However, it would last until May 17th, 1944, before the British Admiralty announced that also the Tarn, which was still under construction, could be taken over. This T-class submarine was taken into service on the 28th of March 1945, as Hr. Ms. Tijgerhaai.