DRAFT Academy ‐ P a g e | 1 Bulk carriers Author Date ScandiNAOS 2007‐03‐19 Chapter Bulk carriers Ships for bulk, neobulk and general cargo Volume ships for volume cargoes More than 60% of the world sea transports are carried with ships bulk, neo‐bulk and general cargo which falls within the dry cargo categories. Some mayor commodities: • • • • • • • • Iron ore and iron derivative like pellets etc. Bauxite Non ferrous ores Coal Phosphates, salt, sulphur, potash etc. Grain and cereals. Forest products Misc. General cargo Generally the value of the above commodities is low and thus the transport costs form a significant part of the value in the port of destination. Consequently the ships for these commodities have to be simple, cheap and cost efficient. Ship size Capacity wise, the following classification is commonly used: • ‐ Big bulk (Cape size) 130.000 tdw and up, the biggest of almost 300.000 tdw. • ‐ Panamax 80.000 tdw • ‐ Handymax 40.000 tdw • ‐ Small bulk 3.000 to 30.000 tdw • ‐ Coasters below 3.000 tdw The size of the ship is a function of what volumes are traded and what shipments can be received. Iron ore from Narvik to Bremerhafen or from Brazil to Japan goes often in shipments of 100.000 tons or more. Pellets from Riga to Västerås are traded in shipments of 5.000 tons www.tts-academy.com 2007-05-02 DRAFT Academy ‐ P a g e | 2 Bulk carriers Figure 1 Deep Sea Bulk Carrier Typical length: 200 – 300 m. Speed: 11 – 16 knots. Figure 2 Coaster bulk carrier Typical length: 70 – 120 m. Speed: 10 ‐15 knots. www.tts-academy.com 2007-05-02 DRAFT Academy ‐ P a g e | 3 Bulk carriers Cargo and cargo handling Ships for true bulk cargo True bulk commodities like ore, coal and grain are mostly handled by conveyor/chute, endless grab buckets, suction devise or grab buckets under crane. A minor share of the bulkships are provided with equipment for selfloading and unloading. The classic ones are the so called “Great Lakers” transporting ore on the Great Lakes in North America. This consists of a conveyor belt in the double bottom and hoppers in the bottom of the holds. Via a vertical conveyor arrangement the cargo is transferred to a conveyor belt on a movable arm that reach out over the wharf. An alternative arrangement sometimes used in chips carriers, the cargo is lifted out of the hold with a crane and grab and dropped in a hopper on a hatch cover and thus distributed on a conveyor belt on deck that leads to an unloading arm. Self‐unloading concepts are utilised, to some extent, in all the categories of bulkships. Ships for semi bulk or neo bulk Semi bulk or neo bulk commodities like pulp, lumber etc are lifted by crane in bundles or loose by special attachments (vacuum lifts etc.). These two groups of commodities have resulted in the development of two basic types of bulk ships: • The bulk ship with self trimming cargo holds where the bottom of the hold athwartships is hopper‐shaped to facilitate unloading with buckets. Often also the upper part of the hold is shaped as an inverted hopper. • The neo bulk ship, where the holds are more or less totally squared, often with flush sides (boxed). www.tts-academy.com 2007-05-02 DRAFT ‐ P a g e | 4 Academy The former group of ships may be regarded as “specialised” and of “big bulk” size. The width is 50 meters and more and the draught above 15 meters. Normally the equipment for loading and discharging of this category of ships is shore based installations in special ports for one commodity only; coal wharfs, iron ore ports, grain ports etc. The ports are tailor made and very efficient and the rate of handling is high. Thousand tons per hour up to several thousand tons per hour is common. Bulk carriers Figure 3 source http://www.columbiariverbarpilots.com/Picture_gallery/ships_crossing_the_bar/14deeploadedbulkcarrierout bound.JPG The neo bulk ships are more versatile in respect of the range of commodities they can carry. To stow lumber, pulp, paper, bagged cargo, palletised and unitised cargo in all forms is a quite straight forward operation. Often the ship carry own equipment for the cargo handling. It may be cranes, derrics, gantry cranes etc Figure 4 source: http://www.shipfoto.co.uk/images/2004%20Photos/Bonasia‐22‐Sept‐2004.jpg www.tts-academy.com 2007-05-02 DRAFT ‐ P a g e | 5 Academy Naturally also many of the true bulk cargoes like coal, grain etc. are possible to handle but in a less efficient and more labour intensive way than the “specialised” bulk ships. Of interest to notice is that the neo bulk ships also may be arranged for the carrying of ISO containers. This is normally not done in regular liner services but rather as an additional resource when the capacity of a line is saturated or the container flow show disturbing unbalance or on project basis. Ships in this category are normally of the Handy size or Panamax size. The lesser size ships; Small bulk and Coasters, are virtually “jack of all trades” and can carry a wide range of cargo may it be bulk, neo‐bulk or general cargo. The concept is directly proceeding the general cargo ship of type “tweendecker” ( a died out breed) and has in general a low efficiency and low costs. Bulk carriers Combination ships. In effort to minimise the number of ballast voyages, bulkships that also could carry liquid cargoes, primarily oil, were developed. Combinations like Ore Bulk Oil (OBO) and Ore Oil (OO) were introduced. The size of these ships was of Panamax and up. In theory the concept was good but in practice few ships were sailing regularily with alternating cargoes. The outcome was rather that the ship was used as a tanker or bulk carrier as the market changed. Relatively few combination ships are built. Figure 5 M/S Svealand 282450 tdw OBO‐carrier Byggd på Eriksberg 1973 Source: http://web.telia.com/~u30207596/svealand1973.htm www.tts-academy.com 2007-05-02 DRAFT Academy ‐ P a g e | 6 Bulk carriers Cargo access Figure 6 Extract from TTS data sheet For the Big bulk ships, hatch covers of side rolling type is prevailing. For Panamax ships, the choice of hatches depends on weather the ship has lifting gear that can be used for the handling of the covers. Gantry cranes for handling pontoon covers or normal cranes or derriks for operation of end folded panels are examples of that. If no gear is available, side rolling, end folded, piggy back or multi‐panel folding covers are common choice. Some commodities like grain etc. are very sensitive to water ingress and require absolute water tightness. For combination ship carrying petroleum is the gas tightness also an absolute requirement. As bulkships by definition have large hatch openings, the different deformation picture of the hull and the hatch panel has necessitated a number of innovative solutions for sealing arrangements as well as arrangements for cleating. www.tts-academy.com 2007-05-02 DRAFT Academy www.tts-academy.com ‐ P a g e | 7 Bulk carriers 2007-05-02 ... Self‐unloading concepts are utilised, to some extent, in all the categories of bulkships. Ships for semi bulk or neo bulk Semi bulk or neo bulk commodities like pulp, lumber etc are lifted by crane in bundles or ... 2007-05-02 DRAFT Academy ‐ P a g e | 3 Bulk carriers Cargo and cargo handling Ships for true bulk cargo True bulk commodities like ore, coal and grain are mostly handled by conveyor/chute, ... ‐ P a g e | 2 Bulk carriers Figure 1 Deep Sea Bulk Carrier Typical length: 200 – 300 m. Speed: 11 – 16 knots. Figure 2 Coaster bulk carrier Typical length: 70 – 120 m.