The aircrews trained continuously until May. Each bombardier completed at least 50 practice drops of inert pumpkin bombs before Tibbets declared his group combat-ready. The ground support echelon of the 509th Composite Group received movement orders and moved by rail on 26 April 1945 to its port of embarkation at Seattle, Washington. On 6 May the support elements sailed on the "SS Cape Victory" for the Marianas, while group materiel was shipped on the SS "Emile Berliner". An advance party of the air echelon flew by C-54 to North Field, Tinian, between 15 and 22 May. It was joined by the ground echelon on 29 May 1945, marking the group's official change of station. It was from Tinian that it carried out the atomic bombings of Hiroshima and Nagasaki.