 In addition to protecting the supply convoy , TF 18 was charged with rendezvousing with a force of four U.S. destroyers , stationed at Tulagi , at 21 : 00 on 29 January in order to conduct a sweep up " The Slot " north of Guadalcanal the next day to screen the unloading of the transports at Guadalcanal . However , the escort carriers were too slow to allow Giffen 's force to make the scheduled rendezvous , so Giffen left the carriers behind with two destroyers at 14 : 00 on 29 January and pushed on ahead . 
