The three transport divisions began forming at different locations throughout late October: Transdiv "A" at Espiritu Santo, Transdiv "B" at Guadalcanal and Transdiv "C" at Efate. Troops were embarked at each location between 28 and 30 October and, in an effort to hide their intentions, different approach routes were taken by each division. On the morning of 31 October, the three divisions rendezvoused at sea and began their approach to Bougainville from southwest of the Solomons. To confuse Japanese reconnaissance aircraft, the convoy conducted a feint towards the Shortland Islands until night fell. Pre-war charts of Bougainville proved to be quite inaccurate, and although aerial reconnaissance and information gathered from submarine patrols had been used to update these, they remained imperfect, particularly with respect to longitude. The charts were also missing details of underwater obstructions and, as a result, the escorting minesweepers hit several uncharted shoals during the approach. One of the APAs, "American Legion" also later ran aground on an uncharted shoal.