Y work was classic interception and decryption of German U-boat signals and Z work was the analysis of “radio fingerprinting”. Radio fingerprinting was the identification of wireless transmitters by the "idiosyncratic characteristics of the signals emitted and the individual radio operators according to the rhythm of their Morse".[1] Y work was much more precise and easier to master, it took much longer to master Z work. Once the Canadians were able to they were so successful at it that the US navy adopted the “Ottawa system”. [2]
By the end of the war there were ten intercept stations in Canada engaged in “Y” work. There were stations at “ Harbour Grace, Botwood, Hartlen Point, Cap d’Espoir, Pennfield, St. Hubert, Ottawa, Strathburn, Portage la Prairie, and Rivers, Manitoba, which were primarily tasked with monitoring of U-boat frequencies.[1] Canada's unique geography meant that the atmospheric conditions in Canada were more favourable for the interception of signals than any other location in the Americas or Brattain. [1] All of Canada’s Y work was done by over 450 ppl across Canada, but the examination unit was instrumental in the creating a formalized decryption processes for the use at the interception posts.
Allied shipping losses caused by German U-boats reached 807,754 tons in November 1942.[2] This was disastrous for the allied wartime effort. The German U-boat effort was highly coordinated, with extensive communications between the boats and the their bases. [1] The volume of communications was ultimately the facet that the allies exploited. This was not easy though, the allies relied heavily on "Y" intercepts which were so numerous that they overwhelmed the capabilities of the allied intercept centres. Y and Z work were essential to the allied victory in the Battle of the Atlantic. The code breaking done by the examination unit was vital for the longer-term strategy, but was too slow to help locate and sink an enemy submarines. [1]