Still Want More Information? Here are the websites I used...
http://en.wikipedia.org/wiki/Submarine_warfare
http://www.history.com/this-day-in-history/germany-ceases-unrestricted-submarine-warfare
http://www.historylearningsite.co.uk/unrestricted_submarine_warfare.htm
http://www.navy.mil/navydata/cno/n87/history/wwii-campaigns.html
http://en.wikipedia.org/wiki/U-boat#World_War_II
http://en.wikipedia.org/wiki/Participants_in_World_War_II
http://en.wikipedia.org/wiki/Submarine_warfare
http://www.history.com/this-day-in-history/germany-ceases-unrestricted-submarine-warfare
http://www.historylearningsite.co.uk/unrestricted_submarine_warfare.htm
http://www.navy.mil/navydata/cno/n87/history/wwii-campaigns.html
http://en.wikipedia.org/wiki/U-boat#World_War_II
http://en.wikipedia.org/wiki/Participants_in_World_War_II