3.1.3. Project 6.4 - Proof Testing of Atomic Weapons Ship Countermeasures (Reference 13). This project evaluated the effectiveness of washdown systemsin reducing theeffects of fallout on ships. Two converted liberty ships, YAG-39 and YAG-40, were instrumented for radiation measurements and equipped with remote controls. A washdown system wasinstalled on YAG-39 only. At Shots BRAVO, ROMEO, UNION and YANKEE,the twoships weresailed into areas of anticipated heavy fallout. During Shots BRAVO and ROMEO, both ships were unmanned and remotely controlled from a P2V-5 aircraft, with a secondary control party aboard USS BAIROKO (CVE-115). Experience from these tests indicated that manning YAG-39 was both desirable and feasible. YAG-39 was manned for Shots UNION and YANKEEbya shielded skeleton crew that received instructions as to the course from the secondary control party on BAIROKO. The ships were boarded after each test and radiation records were retrieved; comparisons of radiation levels onboard each ship indicated the effectiveness of the washdown system on YAG-39., Twofleet ugs, MOLALA and TAWAKONI,participated in this project by escorting the YAGs and debarking their crews before the shots and retrieving and towing the YAGs to Enewetak after the shots. At Shot BRAVO, both YAGs wereretrieved by the tugs and towed unmanned from Bikini to Enewetak. At Shots ROMEO, UNION, and YANKEE, YAG-39 was manned (remanned after Shot ROMEO)and brought to Enewetak under her own power, while YAG-40 was towed back by MOLALA. MOLALAwasalso utilized at Enewetak to aid in the decontamination of the YAGs, if necessary, after each test. MOLALA was involved in these activities for all of the Bikini tests except Shot KOON. TAWAKONI wasinvolved in supporting Project 6.4 for only the first rwo shots (BRAVO and ROMEO). 3.1.4 Miscellaneous Support Activities. As listed in table 1.2, PC-1546 was a unit of the Surface Security Unit (TU 7.3.1). This involved pre- and post-shot security patrols outside the lagoon (primarily ASW patrols) as well as screening and escort assignments with major units when they sortied for each shot. PC1546 was also assigned special tasks that involved sorties to other nearby atolls (Enewetak, Rongerik, Ailinginae) during the operation. USS LST-1146 was assigned to the Transport Unit (TU 7.3.9) for only a brief period during March and April 1954. Its primary duties were to transport passengers andfreight between Bikini and Enewetak Atolls.