OBO carrier

A OBO carrier is a vessel that can trade with both Oil, Bulk and Ore cargoes, hence the name. The idea was that it would function as a tanker when the tanker markets were good and a bulk / ore carrier when these markets were good. It would also be able to take "wet" cargo (oil) one way and "dry" cargo (bulk cargoes / ore) the other way, thus reducing the time it had to sail in ballast (i.e. empty).

The first OBO carrier was the Naess Norseman, built at A. G. Weser for the company Norness Shipping, controlled by the Norwegian shipowner Erling Dekke Næss.

Næss was instrumental in conceiving the new type of vessel, together with his chief naval architect T. M. Karlsen. The Naess Norseman was delivered in November 1965, the vessels data was as follows: Length 250 meter, beam 31,6 meter, draft 13,5 meter, 37,965 gross tonnes.

The OBO carrier quickly became popular among shipowners around the world and as today several hundreds of this type of vessel have been built. The ship type had its glory days in the early 1970s. In the 1980s, it became clear that the type required more maintenance than other vessels. Also, it was expensive to "switch" from wet to dry cargoes, and it took valuable time. If you had carried oil, you could switch to carrying ore or other dirty bulk cargoes, but not grain or other clean bulk cargoes. As the 1970s-built OBO vessels become older, most of them were used either as pure tankers or as pure ore carriers.

In the 1990s, a smaller number of OBOs from 70,000 metric tons deadweight (DWT) to 100,000 DWT were built for the account of Danish and Norwegian shipowners.