Changes

With the retention of the Fleet in Hawaiian waters after the conclusion of Fleet Problem XXI, ''Yorktown'' operated in the Pacific off the west coast of the United States and in Hawaiian waters until the following spring, when the success of German U-boats preying upon British shipping in the Atlantic required a shift of American naval strength. Thus, to reinforce the Atlantic Fleet, the Navy transferred a substantial force from the Pacific including ''Yorktown'', a battleship division, and accompanying cruisers and destroyers.

With the retention of the Fleet in Hawaiian waters after the conclusion of Fleet Problem XXI, ''Yorktown'' operated in the Pacific off the west coast of the United States and in Hawaiian waters until the following spring, when the success of German U-boats preying upon British shipping in the Atlantic required a shift of American naval strength. Thus, to reinforce the Atlantic Fleet, the Navy transferred a substantial force from the Pacific including ''Yorktown'', a battleship division, and accompanying cruisers and destroyers.

''Yorktown'' departed [[Pearl Harbor]] on 20 April 1941 in company with USS ''Warrington'' (DD-383), USS ''Somers'' (DD-381), and USS ''Jouett'' (DD-396) and headed southeast, transiting the Panama Canal on the night of 6 and 7 May, and arrived at Bermuda on the 12th. From that time to the entry of the United States into the war, ''Yorktown'' conducted four patrols in the Atlantic, ranging from Newfoundland to Bermuda and logging 17,642 miles steamed while enforcing American neutrality.  Although Adolph Hitler had forbidden his submarines to attack American ships, the men who manned the American naval vessels were not aware of this policy and operated on a wartime footing in the Atlantic.

''Yorktown'' departed [[Pearl Harbor]] on 20 April 1941 in company with USS ''Warrington'' (DD-383), USS ''Somers'' (DD-381), and USS ''Jouett'' (DD-396) and headed southeast, transiting the Panama Canal on the night of 6 and 7 May, and arrived at Bermuda on the 12th. From that time to the entry of the United States into the war, ''Yorktown'' conducted four patrols in the Atlantic, ranging from Newfoundland to Bermuda and logging 17,642 miles steamed while enforcing American neutrality.  Although Adolf Hitler had forbidden his submarines to attack American ships, the men who manned the American naval vessels were not aware of this policy and operated on a wartime footing in the Atlantic.

On 28 October, while ''Yorktown'', battleship USS ''New Mexico'' (BB-41), and other American warships were screening a convoy, a destroyer picked up a submarine contact and dropped depth charges while the convoy itself made an emergency starboard turn, the first of the convoy's three emergency changes of course. Late that afternoon, engine repairs to one of the ships in the convoy, ''Empire Pintail'', reduced the convoy's speed to 11 knots.

On 28 October, while ''Yorktown'', battleship USS ''New Mexico'' (BB-41), and other American warships were screening a convoy, a destroyer picked up a submarine contact and dropped depth charges while the convoy itself made an emergency starboard turn, the first of the convoy's three emergency changes of course. Late that afternoon, engine repairs to one of the ships in the convoy, ''Empire Pintail'', reduced the convoy's speed to 11 knots.