In December 1946, 166 Seabees sailed from Port Hueneme on the USS Yancey and USS Merrick assigned to Operation Highjump. They were part of Admiral Richard E. Byrd's Antarctic expedition. The U.S. Navy was in charge with "Classified" orders "to do all it could to establish a basis for a (U.S.) land claim in Antarctica". The Navy sent the Seabees to do the job starting with the construction of Little America (exploration base) IV as well as a runway for aerial mapping flights. This Operation was vastly larger than IGY Operation Deep Freeze that followed.