Rubuta ci gaba don wannan sakin layi - Bayan Harin Japan a kan Pearl Harbor da kuma shigar da Amurka a cikin yakin duniya na biyu, an sake kiran Foster zuwa aiki tare da mukamin Kwamandan a cikin Naval Reserve kuma shugaban kasar Franklin D. Roosevelt ya ba shi aikin kai tsaye don gudanar da bincike na musamman na jirgin ruwa. Daya daga cikin ayyukansa na farko shi ne gudanar da bincike a yankin Canal na Panama
biyo bayan jerin korafe-korafe daga Laftanar Janar Daniel Van Voorhis, Kwamandan Rundunar Tsaro ta Caribbean a kan hadin gwiwar Sojoji da Sojojin Ruwa.