• US industrial prod. irrelevant without control of Shipping routes across Atlantic -. to Britain and to USSR
    • Achieved thru bitter struggle + high cost
1.
Sept 1939 Canada entered war on Br. Side
Canadian Troops crossed Atlantic defend Br. + fight in North Africa, Italy during op. overlord
Canada sent vast quantities food + raw materials across Atlantic to Br. from very start of war
2. US entered war in Dec 1931 but played imp. role before that.
1941 Roosevelt set up lend lease scheme supplied vast amounts of food + raw materials support Br. War efforts against Hitler.

Similar scheme sending supplies to USSR after 1941.

supplies to Br. and USSR transported by Merchant ships
were grouped in convoys with naval escorts could be protected against German submarines.(U-boats)
3.US military power worthless if it could not cross Atlantic to bolster allies.

U-boats very effective early in battle of Atlantic.

1940 Germans sank over 1000 ships quarter of Br. Merchant fleet.

next 2 years even worse:
1941: 1,300 allied ships lost.
1942: 1,661 ships.

Jan 1943 Br. Navy had only 2 months of oil supply left.
4. Tide began to turn 1943.
Br. Intelligence able to break secret codes used by U-boats.
allowed allied convoys steer clear of U-boats hence ensuring Br. + USSR had resources fend of axis powers.

New weapons + tactics also developed to counter the U-boats.
5. Another key factor sheer scale + spread of US industrial prod.

US shipyards began building cargo ships called liberty ships.

1943 3 ships completed daily.

Soon US building more ships than U-boats could sink
6. Second half of 1943 Allies sank 141 U-boats.

Germans now losing more U-boats than they were sinking Allied ships.

March 1944 Germans called off U-boat campaign though losses due to U-boat attacks continued until war’s end in 1945.