Ships from Norway to Australia 1869

Hi I have Australian naturalisation (1910) documents for my great great grandfather William (Johan) Janson born 26 August 1853 Christiania, Norway which stated he emigrated in 1869 from Norway to Melbourne, Victoria Australia. I cannot read the name of the ship. It looks like the first letter is an I or an S followed by n and then o. The o has a dash above and below. If someone could help me with this it would be appreciated as it is a long search for this ancestor and his Norwegian origins. Thanks Gen Campbell