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MOORING BY GIANT ELECTROMAGNETS


  Our colleague, captain Ardillon, has translated for us an article published in New Scientist of January 17th, 2003.


      Soon a simple pressure on a button should be sufficient to moor a ship. In 2003 The port of Rotterdam should do a full scale test to moor a large container ship using a series of electromagnets arranged along the quay. If the result is good, such a system could save 5 million euros per year in mooring costs and decrease the average calling time of 40 minutes for these vessels.


      


      The “mooring magnets” were excluded in the past in order to avoid damage the roro vessels cargoes sensitive to the magnetic field, such as TVs, computers, etc, whose cathode ray tubes are especially sensitive to the magnetic fields. Moreover, such magnetic fields could have prevented the lifting of steel containers from deck or holds.

      But now, “magnetic” specialists from the Delft university of technology in the Netherlands think they are able to develop electromagnets whose magnetic field would not penetrate too much into the vessel's spaces.

  • a concentrated field

          Each mooring magnet generates a field of 1Tesla. The magnets are 13 m in length and are thick. Magnetic stems are placed side by side according to a drawing that concentrates the magnetic field at the ends of the stems. According to the designers, the proximity from each other of the stems rather ensures a mutual attraction of the fields than their far away dissipation. They are trustful on the fact that their magnets should not affect anything inside the ship.
          According to calculation, 52 of these magnets arranged along a quay would be able to maintain alongside a 400 m length container ship. The magnets would be strong enough to be able to keep a ship moored with wind up to force 12, and would not be affected by waves and wash coming from other vessels passing along. To allow the vessel to follow the tidal moves, the magnets would be periodically cut for a time, short enough not to allow the vessel to move off the quay. This is the very point to check during the tests.

  • Concurrence

          Another system is currently developed by the company “Mooring System” of Christchurch in New Zealand. The system uses vacuum suction cups stuck on hull, it is entirely mechanical and consumes electricity only for mooring, on the contrary the Dutch system is a large-scale electricity consumer and thus predisposed to electric breakdowns. This would be thwarted by availability of electric generators. On another side, the magnets would be a system lighter than the vacuum systems and thus easier to use in an harbor with a very heavy traffic.
          However, the tests in Rotterdam will take place with a back up safety, indeed the vessel will be moored, normally with good old hawsers just in case …

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