Enlistment district
| Name | Details |
|---|---|
| M/T Orator | Build year 1953 |
| Fullrigger Oregon | Build year 1874 |
| M/S Orient | Build year 1957 |
| M/S Orinoco | Build year 1951 |
| Bark Orion | Build year 1867 |
| M/T Orion | Build year 1936 |
| M/S Orion | Build year 1963 |
| Bark Orion | Build year 1874 |
| M/S Orion | Build year 1957 |
| D/S Orion | Build year 1909 |
| Bark Orion | Build year 1877 |
| D/S Orion | Build year 1870 |
| Bark Orion | Build year 1849 |
| M/S Orion I | Build year 1907 |
| D/S Oris | Build year 1949 |
| Galeas Oscar | Build year 1875 |
| M/S Oslo | Build year 1962 |
| D/S Oslo | Build year 1929 |
| Skonnert Ossian | Build year 1868 |
| Ole Osufsen | Born March 13, 1844 in Herefoss |
| Gunnar Osuldsen | Born October 30, 1896 in Myrene,Arendal |
| Jørgen Osuldsen | Born January 27, 1898 in Landvik |
| Nils Svendsen Osuldsen | Born March 6, 1900 in Arendal |
| Peder Johan Osuldsen | Born January 29, 1909 in Barbu, Arendal |
| Rikmann Osinius Osuldsen | Born November 25, 1887 in Arendal |