Since preparations were to be secret, only rumors hinted at the entire 9th Australian Division would be removed from Tobruk as the 18th Brigade had been. There were necessary warnings to units that would be pulled out during the next moonless period. The units that received notice were the 2/1st Pioneer Battalion, the 24th Brigade except for the 2/43rd Battalion, the 2/12th Field Regiment, the 2/3rd Anti-Tank Regiment, along with several batteries from the 3rd RHA. The 2/7th Field Company was attached to the 24th Brigade, so they would leave as well. The British 16th Brigade would replace the Australian 24th Brigade. There was further shuffling of units to free up the units that would leave Tobruk.
The 2/12th Field Regiment had been very active during their time in Tobruk. They had fired off some 56,000 rounds and had lost 24 men killed and 24 wounded. A group of the 2/12th left Tobruk on the night of 18 September. The 2/12th would trade places with the 144th Field Regiment at Amiriya in Egypt. The 144th took over the odd collection of guns from the 2/12th Field Regiment and a disreputable set of gun tractors. In Egypt, the 2/12th Field Regiment received good 25pdrs and gun tractors left behind by the 144th Field Regiment.
The way things worked in the topsy-turvy world of the British military family, some men in Tobruk were stuck with Great War-vintage 18pdr guns, while other units away from the enemy were equipped with the latest gear. The men in Tobruk did not know of this situation so they had no problem using whatever guns they could get.
When the 2/1st Pioneer Battalion left Tobruk, that was their last association with the 9th Australian Division. They had been involved in heavy action since 1 May 1941, when they had built a line to defend against the German attack that penetrated the Tobruk perimeter. They would be replaced in the future by the 2nd/3rd Pioneers.
During the dark nights in September, 29 tanks were transported to Tobruk by A-lighters. The old 3rd Armoured Brigade headquarters was replaced by the 32nd Army Tank Brigade. The incoming tanks belonged to the 4th RTR. At their arrival, the tanks were still under the control of General Morshead, the fortress commander. He only had limited control, however, since General Morshead was required to request that the tanks be made available for attacks. The request was always granted, however.
Tbe relief operation was called "Operation Supercharge". The British Royal Navy excuted the withdrawal from 17 September until 27 September 1941. They used two fast minelayers of the Abdiel class and about 11 destroyers. Only any one night, one minelayer and three destroyers would enter and leave Tobruk's harbor. They stayed only two hours each night. Three cruisers of the 7th Cruiser Squadron provided cover for the withdrawal. They were concerned that Axis air power would be used against the evacuation, but that did not happen. This is based on account in Vol.III of the Australian Official History.