included observation, instrument and communication towers, radio beacons, seismic huts, photo reference crosses, general base and recreational facilities, as well as dredging the lagoon. In addition, recreational facilities were constructed on Japtan Island for the ships crews of the Operation. The Battalion also assisted the relocation of the natives. They disassembled both the Community center and church for reassembly on Rongerik Atoll. In August the battalion was decommissioned with men transferred to CBD 1156 that was then commissioned on Bikini. The TU 1.8.6 designation transferred to the CBD. CBD 1156 remained for nine days after the second test. UDT 3 was designated TU 1.1.3 for the operation. On 27 April 1946, seven officers and 51 enlisted embarked at CBC Port Hueneme for Bikini. Their assignment was to retrieve water samples from ground zero of the Baker blast. In 1948, the displaced bikinians put in a request that a channel to the island Kili where they had been relocated be made. This was given to the Seabee detachment on Kwajelin who requested UDT 3 assist. The 121st CB was decommissioned in December and re-designated CBD 1504. In January 1947 CBs 104 and 105 were reactivated. The 30th NCR was home-ported on Guam composed of CBDs 1501-13 and NCB 103. In 1949, the 103rd was made a Mobile Construction Battalion (MCB) while CBs 104 and 105 were made Amphibious Construction Battalions(ACBs). From 1949 until 1968 CBs were designated MCBs. In 1949, MCB 1 was reactivated at Naval Amphibious Base Little Creek, VA. In June 1950 the NCF totaled a few thousand. Korean War The outbreak of the Korean War led to a call-up of 10,000 from the Seabee Reserve. Seabees landed at Inchon during the assault, installing causeways dealing with enormous tides and enemy fire. Their actions there and elsewheres underscored the necessity of having CBs. During that war the authorized size of a CB was 550 men. When the truce was declared there was no CB demobilization as there had been at the end of World War II. During the Korea, the U.S. realized the need of an air station in the region. Cubi Point in the Philippines was selected. Civilian contractors were approached for bids. After seeing the Zambales Mountains and the maze of jungle, they claimed it could not be done. The Navy then turned to the Seabees. The first to arrive was CBD 1802 to do the surveying.