Tank bulk carrier
As ore-bulk-oil carrier refers to various bulk cargo ship types for simultaneous or alternate transportation of crude oil and ores , as well as some other bulk materials .
The ore / oil cargo ship , or O / O-Carrier (from the English O il / O re for oil and ore) is the older variant for certain services with mixed cargo volumes of crude oil and ores.
The oil / bulk / ore freighter , or OBO carrier (from O il B ulk O re for oil, bulk and ore) is therefore particularly suitable for particularly flexible services with mixed cargo volumes of crude oil, ore and other bulk cargo in Suitable for regions where otherwise only one-sided loading would be possible.
history
Although the first simple combinations of oil and ore ships were tried out as early as the end of the 19th century, when the first specialized ore ships and tankers were being developed, the direction of development was initially rather vague (see also the ships Vaderland and Neptun ). For reasons of trim and stability, ore ships in particular were equipped with large ballast water capacities in relation to the holds, which could be used for oil transport in order to avoid uneconomical ballast journeys.
The G. Harrison Smith from 1921 can be seen as one of the first consistently to be used as a combined ship for the ore and oil trade. The shipping company International Petroleum Company drove the G. Harrison Smith Erze from the South American west coast to Maryland on the North American east coast, from there in ballast to Mexico, where they loaded oil again for the west coast. Due, among other things, to higher fees in the Panama Canal (tankers had a higher, i.e. unfavorable measurement), this service was not worthwhile, so the ship continued to operate as a conventional ore carrier.
Another early example was the engine-powered, oil / ore freighters Svealand and Amerikaland (15357 GRT) of the shipping company Angfartygs A / B Tirfing, which belongs to the Swedish Broström group. The ships built in 1925 at the Deutsche Werft in Finkenwerder transported ore from Cruz Grande in Chile to Baltimore . They were chartered to Bethlehem Steel for 20 years . A theoretically possible transport of crude oil was not carried out because of the high canal passages with approval as a tanker.
Around the mid-1950s, ore / oil ships began to be developed that no longer loaded the oil to be transported exclusively into the tanks surrounding the ore holds, but also into the actual holds themselves. One of the first ships of this type, which was in principle valid until the end, was the Californian , which was converted in the United States in 1954 for the New York shipping company Ore Transport Company .
Another innovation was bulk tanker ships, first built in 1957, with the suitability for dry cargo in larger clearings . For the first time, these ships could also transport oil or lighter bulk goods instead of ore and oil.
The last major steps in the development of the new OBO-Carrier ship type were Mando Theodoracopulos , which was put into service at the end of 1959, and Naess-Norseman, which was delivered by Bremen AG Weser- Werft in November 1965 . The Mando Theodoracopulos , designed by Panagopulos & Associates in New York , had the disadvantage of a continuous central longitudinal bulkhead and the large number of 18 hatches, which slowed down cargo handling. The Naess-Norseman , whose development was led by Erling Dekke Næss, the owner of the shipping company Norness Shipping and its chief shipbuilding engineer TM Karlsen, finally coined the generic term “OBO”.
The emergence of the real OBO carriers was accompanied by a brief phase of increasing the size of these types of ships, which came to an end as early as the 1970s. The numerical development of the OBO carrier also reached its peak in the early 1970s and quickly subsided again in the 1980s, as the ships, which were already around 10% above the price of pure tankers when they were built, not only proved to be significantly more demanding in terms of maintenance and in technical maintenance, but also required a relatively long time to switch from one type of load to another. The overwhelming number of these ships were therefore operated as pure bulk carriers (and then mostly as pure ore ships) or tankers with increasing age. For the reasons mentioned, a larger percentage of these ships were quickly sold for demolition as unprofitable.
It was not until the 1990s that some Scandinavian shipping companies began to order a number of smaller OBO carriers , for example in the Aframax segment.
Loading space arrangement
Combined tank-bulk carriers, due to their design, have to meet certain criteria that go beyond those of conventional tankers or bulk carriers. On the one hand, they must be able to cope with the demanding loading and unloading operations of dry cargoes, in particular ore handling, and on the other hand, the oil cargoes must be able to be transported clean and gas-tight. The numerous pipelines for tank operation are to be installed in such a way that they are not damaged during dry loading. With early designs, the bulk goods were loaded in the central cargo holds, the cargo and ballast tanks were arranged to the side and below. In later designs, from around the 1950s, oil was also transported in the central cargo holds, which made gas-tight hatch covers necessary. During the further development from the O / O-Carrier to the OBO-Carrier, the shape and size of the dry cargo holds changed (see illustrations).
literature
- Rolf Schönknecht, Uwe Laue: Ocean freighters of world shipping . Volume 2. transpress Verlag, Berlin 1988, ISBN 3-344-00282-1 (library of ship types).
- Alfred Dudszus, Alfred Köpcke: The big book of ship types . Weltbild Verlag, Augsburg 1995, ISBN 3-89350-831-7 (licensed edition by transpress, Berlin).
See also
Individual evidence
- ↑ Ship data at Miramar Ship Index ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Ship data at Miramar Ship Index ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Ship data at Miramar Ship Index ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ^ Clyde L. Jacobs: Development of the Specialized Dry Bulk Carrier , In: Marine Technology , Vol. 20, No. 1, pp. 13-20.
