What was the impact had on german u-boats on shipping in the atlantic during ww2

Canada was supplying food, supplies and soldiers out to Europe, but the German U-Boats were set up stealthily and attacked the Canadian ships, cutting off supply routes and depriving the Britains source of food and such. The codes were cracked so this was stopped but it had a real impact on the war at the time. Hope this helps!

By providing data about careers and annual mean wages.