eventually 14 Axis submarines to fall victim to T-class submarines. On 5 July 1941, Tigris accounted for another Italian submarine, the Michele Bianchi. The Iron Ring patrols were discontinued after the infamous 'Channel Dash' in February 1942. Mediterranean T-class submarines began to operate in the Mediterranean from September 1940 onward. This was the theater in which the T class were most heavily engaged in operations and correspondingly suffered proportionately heavy losses. Operations in the Mediterranean posed several substantial challenges for British submarines and the T class in particular. Firstly, the Italian Regia Marina, almost uniquely among the Axis navies, had devoted a substantial amount of resources and training to anti-submarine warfare. Equipped with their own version of sonar, the ecogoniometro (ECG), possessing excellent escort vessels, and making extensive use of mines, the Italians were to prove the most successful of the Axis powers at destroying Allied submarines. The Mediterranean Sea was also characterised by calm, shallow, and unusually clear waters compared to the North Atlantic. Submarines could often be spotted from the air even when submerged, and the shallow waters made deep diving to escape attack difficult or downright impossible. Having been designed for operations in the Far East, the T boats were substantially larger than the standard German Type VII U-boat, and thus they were more vulnerable to detection and mines. Conversely, the large sizes of the T-class boats gave them substantially greater endurance and range compared to the smaller standard Royal Navy submarines like the S and U classes. This allowed them to operate successfully from the British bases of Alexandria and Gibraltar, which were located at considerable distances from Axis waters. The British submarine campaign in the Mediterranean was primarily targeted at Axis convoys from Italy to North Africa supplying the Italian army and German Afrika Korps fighting the British Commonwealth forces in North Africa. Axis airpower made it extremely hazardous to use surface warships in this role, and until the Allies were able to establish air superiority over Malta the burden of the anti-shipping campaign would fall on the submarines based in the Mediterranean. British submarines did not operate surfaced during the day in the Mediterranean as it was far too hazardous thanks to Axis airpower, surfacing to recharge only at night. By contrast, Axis submarines tended to operate surfaced in broad daylight, a habit described by British submariners as 'truly reprehensible'. T-class submarines thus proved