Again, the Army under Halleck did not grasp the opportunity that was provided. He failed to send even a small body of troops to aid the ships, and soon Farragut was forced by falling water levels to withdraw his deep-draft vessels to the vicinity of New Orleans. The Army did not attempt to take Vicksburg until November, and then the Army was under the leadership of Maj. Gen. Ulysses S. Grant, after Halleck had been called to Washington to replace McClellan as General-in-Chief.