This graph shows the increased numbers of Allied ships sunk by U-Boats by month during WW2. Source: http://romanushistory11.wikifoundry.com/page/The+Battle+of+the+Atlantic

This graph shows the increased numbers of Allied ships sunk by U-Boats by month during WW2.

This graph shows the increased numbers of Allied ships sunk by U-Boats by month during WW2. Source: http://romanushistory11.wikifoundry.com/page/The+Battle+of+the+Atlantic