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Naval Engineering

Clean and efficient cargo ship

Brazilian ship has innovative system for loading and unloading 400,000 tons of iron ore

valeVale Brasil in Rio de Janeirovale

The main feature of the vessel Vale Brasil, the biggest bulk carrier currently in operation in the world at 362 meters long, 65 meters in the beam and with capacity to carry 400,000 tons on every voyage, is its loading and unloading efficiency. This is the result of an innovative engineering project developed by Projemar, a naval engineering company from Rio de Janeiro, in partnership with the mining company Vale. ‘The chief distinguishing feature of this vessel is that each of its seven holds is loaded at the same time, which eliminates the waste of time and energy as the ship loader moves several times along the quay,” says Fábio Brasileiro, Shipping Director at Vale. “The architecture of the holds was also designed so that they can be loaded and unloaded as fast as possible.” The reduction in carbon emissions per ton of iron ore transported is another favorable aspect of this vessel.

The decision to invest in a vessel capable of carrying the weight equivalent of 487,000 low-price automobiles began some eight years ago, when technicians from Vale’s shipping and marketing teams noticed that, because of the huge distance between Brazil and Asia, the main consumer market for Brazilian iron ore, it would be necessary to have lower freight costs. They therefore decided to build a more efficient and more competitive ship. The concept and engineering project are Brazilian, but construction, which took 20 months, was undertaken by a South Korean shipyard, Daewoo Shipbuilding & Marine Engineering. South Korean shipyards, like their Chinese counterparts, are able to build super-ships in series and have the labor force and facilities available for such. The Vale Brasil is the first of 19 ships ordered by the company from Asian shipyards. Seven of them are being constructed at Daewoo, at a cost of US$ 748 million, and twelve are being contructed at a Chinese shipyard, Rongsheng Shipbuilding and Heavy Industries, for US$ 1.6 billion. Forecast delivery dates are between 2011 and 2013. The Brazilian naval industry for constructing large vessels, which used to be one of the most important in the world in the 1970s, lay practically abandoned for decades and only more recently has it begun to record an effective return to activity because of orders from Petrobras, reinforced by the pre-salt layer oil reserve discovery. There is still a lot to be done, like the setting up of shipyards in Alagoas, Rio Grande do Sul, Rio de Janeiro, Pernambuco and Espírito Santo, which will be necessary to account for the ship and platform orders that have been planned in the Petrobras program.

 Model at USP simulates the docking of the ship at the Ponta da Madeira Terminal

Eduardo CesarModel at USP simulates the docking of the ship at the Ponta da Madeira TerminalEduardo Cesar

Less carbon
In May, in Oslo, Norway, the Vale Brasil received the Nor-Shipping Clean Ship Award because it emits 35% less carbon per ton of iron ore transported than the traditional ships of around 200,000 tons that are used for the same purpose. The Nor-Shipping Fair is one of the world’s main shipping events and is organized by the Portuguese Naval Society every other year. “The reduction in carbon emissions arises from the technology used in the engine, which optimizes the burning of fuel, sensing and the generators,” says Brasileiro. “The Vale Brasil has a characteristic that sets it apart from the other bulk carriers in operation. It is possible to fill an entire hold without a sequential loading plan, as is usual in order for the ship not to suffer any damage,” says professor Paolo Alfredini, from the Department of Hydraulic and Environmental Engineering from the Polytechnic School at the University of São Paulo (USP), who coordinated the maneuver simulation trials in the reduced-size physical model of Vale’s Ponta da Madeira Terminal in São Luís, Maranhão. A ship loader is a structure that has a conveyor belt that loads the ore into the hold of the vessels. It is necessary to load traditionally-designed bulk carriers following a pre-established load compensation plan, so that no imbalance is caused, or even a rupturing of the hull. “The innovative loading concept results in a substantial increase in the port?s operating productivity.”

Old partnership
In size, the Vale Brasil is sixth on the list of the world’s biggest ships, currently led by the Emma Mærsk, a container ship from Denmark that is 397 meters long, 56 meters in the beam and capable of carrying 11,000 containers with a gross weight of 123,200 tons; since 2006 it has been operating between Asia and Europe. Until 2010 the position was held by the Norwegian super-tanker, Knock Nevis, 458 meters long and 69 meters in the beam, which is no longer in operation. Giant sizes also constitute a problem, because there are few ports capable of receiving vessels of this type.

USP, a partner of Vale’s since the end of the 1970’s, collaborated to the success of the project with simulation of force trials on the maneuver system. These were carried out in a large test facility at the laboratory attached to the Department of Hydraulic and Environmental Engineering at the Polytechnic School (Poli), in which the model currently occupies almost 1000 sq. m. A reduced size physical model of the ship reproduces a geometric, cinematic and operating similarity to Vale’s Maranhão terminal. “All the maneuvers carried out at our marine terminal were simulated on USP’s model,” relates Brasileiro. The trials, carried out under the coordination of professor Alfredini, included everything from how the ship behaves when moored at the dock to the issue of its navigability and the security of its operations. “One of the trials, for example, simulated the forces produced by the ocean currents on the ship’s mooring cables before it first tied up in São Luís,” recounts engineer Juliano Philippi, who is responsible for the trials, and who in 2010 defended his Master’s thesis, supervised by Alfredini, on the simulation of non-crewed ship maneuvers. “In this region the influence of the waves is not significant, but the influence of the ocean currents is,” says Alfredini. “In Maranhão the tide rises and falls by more than six meters. These changes in level, which occur over a period of a little more than six hours, generate very strong currents.”

076-079_NaviodaVale_186Reduced scale
With the help of a radio-controlled system, the trials done with the physical model reproduce ship maneuvers, like docking (arrival) and undocking (leaving), with the ship empty and completely loaded, and the tide level. The pilots, who are responsible for the maneuvers of the ship in port, command the radio control with orders for the functioning of the ship?s machinery, the rudder and the action of the tug-boats being given to a team that is in another room. The commands are issued in the form of radio-frequency signals that are picked up by the ship. The maneuvers are seen by the pilot via two cameras on the bridge of the model ship, which reproduces the image of each action as if it were a real operation in the port. In other words, it is as if the pilot were on the command bridge of the vessel. The first physical model of the terminal operation on a reduced scale began operating at USP in 1979 for the Carajás Project. It was commissioned by Amazônia Mineração, a partner of Companhia Vale do Rio Doce Mineração, Vale?s former name, and by an American company, U.S. Steel. The model was expanded four times, accompanying the growth of the Ponta da Madeira Terminal, which initially had a single pier and as from next year will have four, the last one specially built to receive the Vale Brasil. Since 1991, when the analogic simulation of shipping maneuvers was developed, more than 1,600 simulations have been carried out for the large ships that use the Maranhão terminal.

A replica of the Vale Brasil was built out of fiber glass and afterwards received the engine, rudder and mechanisms that activate these mechanisms and the tugs by radio control. “As the geometric scale of the physical model is 1/170, the trick used to simulate a tug pulling or pushing the ship is done with fans embedded within the ship’s hull,” says Alfredini. “By means of appropriate calibration they reproduce the effect of tugs without needing their physical presence.” Because of the model’s reduced size the timescale is also 13 times faster than in real life. As a result, the pilot has to carry out the maneuvers far faster than if he were commanding the ship in the port.