Whakaotihia te rerenga e whai ake nei: I te 18 o Tihema 1855 ka uru a Stephenson ki te Royal Navy, ka noho hei Naval Cadet i HMS "St Jean d'Acre", i whakahaua e tana matua keke a Henry Keppel, ka mahi i te Moana Pango i te Pakanga o Crimea. Mai i te Mahuru 1856 ki te Paenga-whawha 1857 i mahi a Stephenson i raro i a Keppel hei kaiako i te HMS "Raleigh", i mahi i nga East Indies me Haina i te wa o te
Ko te Pakanga Tuarua o Ingarangi-Haina, tae noa ki te wa i pakaru ai tana kaipuke i te taha o Macau i te wa i pa ai ki tetahi kohatu kaore ano kia tohua. I whakaorangia te kapa katoa. I te marama o Hune 1857 i mahi ia hei Midshipman i HMS "Pearl", e mahi ana me te "Pearl's Naval Brigade i te wa o te Indian Mutiny o 1857, i te wa i whakahuatia ai ia i roto i nga Despatches e toru nga wa. I te Hune 1861 i whakatairangahia ia hei kaitiaki i roto i te HMS "Emerald", e mahi ana i te Channel Squadron.