Rubuta ci gaba ga wannan sakin layi - Daga 1902 zuwa 1904, Belknap yana aiki a Ofishin Jirgin Ruwa na Navy. Ya yi aiki a cikin jirgin ruwa daga 1904 zuwa 1905, kuma daga 1905 zuwa 1906 ya kasance mai kula da jirgin ruwa kuma daga bisani ya zama babban jami'in jirgin ruwa. An ba shi mukamin Laftanar Kwamandan a ranar 8 ga Yuli 1905. Daga 1907 zuwa 1910, shi ne dan majalisar na Amurka zuwa Jamus a Berlin, kuma daga 1908 zuwa 1909 ya kasance dan majalisar na ruwa zuwa Italiya a Roma da kuma dan majalisar na ruwa zuwa Austria-Hungary a Vienna. Bayan mummunar girgizar kasa da tsunami
a Messina, Italiya, a ranar 28 ga Disamba, 1908, ya zama darektan jirgin ruwan agaji na Red Cross na Amurka wanda ya amsa bala'in kuma ya kula da gina gidaje 16,000 a wurare daban-daban guda tara a kusa da Messina da Reggio di Calabria. A cikin 1910, ya yi aiki a matsayin jakada na musamman kuma mai ba da shawara na sojan ruwa ga tsohon Shugaba Theodore Roosevelt a jana'izar Sarki Edward VII a Burtaniya.