 Nyorai kupfuurira kweiyi ndima - Pana 21 December 1914, Arnold-Forster akanyoresa muRoyal Naval Volunteer Reserve, achibatanidzwa neDhipatimendi reZvokutengeserana paAdmiralty kwaakabatanidzwa mukuronga kuvharirwa kwezvikepeGermany. Musi wa 29 Zvita 1914, akasimudzirwa pachinzvimbo cheLieutenant, uye kuna Lieutenant Commander musi wa 4 Chikumi 1916. Muna 1919 akashanda paParis Peace Conference, uye akanyora nhoroondo yeRoyal Navy yekudzivirira. Akadzingwa basa musi wa19 December 1919. 