We have so far registered 4,561 shipyards
| Name | | Ottensener Eisenwerk A/G, Hamburg, Tyskland |
| Otterdals Interessentskaps Skibsværft, Kristiansand |
| Otters Værft, Lund, Kristiansand. |
| Ottesens Skibsbyggeri, Sagvåg, Stord |
| Otto Nilsen, Sagvaag, Bergen |
| Ottøy Ryfylke. Skipsbyggmester Paul Otøen |
| O. Tønnesen, Lillesand |
| O. Ulvans Båtbyggeri A/S, Sandstad |
| Ouse Shipbuilding Co.Ltd., Goole, UK |
| Owens & Duncan, Quebec |
| O/Y Helsingin Telakka, Helsingfors |
| O/Y Laivateollisuus A/B, Åbo, Finland |
| O/Y Navire A/B, Nadendal, Finland |
| O/Y Wärtsila A/B, Helsingfors, Finland |
| O/Y Wärtsila A/B, Turku, Finland |
| O/Y Wärtsilä A/B, Åbo, Finland |
| Paaske, Horten |
| Pacific Bridge Co, Alameda, CA, USA |
| Pacific Bridge Co., San Francisco, CA, USA |
| Pahl Schiffswerft, Finkenwerder, Hamburg |
| Palmer Bros. & Co., Newcastle, UK |
| Palmers Co. Ltd., Newcastle, UK |
| Palmer`s Engineering Co. Ltd. Jarrow |
| Palmers S.B. & Iron Co.Ltd., Newcastle. |
| Palmers Shipbuilding & Iron Co.Ltd, Jarrow, UK |
