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Posted on 01/22/2003 6:15:48 AM PST by vannrox
Giant electromagnets to moor ships Maarten Keulemans, Amsterdam
The gentle press of a button could soon be all it takes to keep a giant ship secured to the dockside. The port of Rotterdam in the Netherlands is getting ready to test an experimental system later in 2003 that will use a series of strong electromagnets built into the quay to moor giant container ships. If it works, they say the system could save them around 5 million Euro a year in labour costs, and speed ships' average turnaround times by 40 minutes.
Mooring a ship can be a time-consuming, labour-intensive affair in which dock workers grab ropes hurled from the deck of the incoming ship and secure them to the dockside. Alternatives proposed in the past range from robotic arms that pull the ship to the shore, to outlandish underwater elevators that raise the vessel up out of the water and hold it secure at the dockside, free from interference by the tides.
Docking magnets have always been ruled out in the past because of the risk of damaging sensitive cargo or on-board equipment, such as TV sets and computer monitors. Cathode-ray tube screens in TVs and monitors are specially vulnerable to magnetic interference. If their metal chassis become magnetised, the field sends the electron beam off centre, distorting colours. And such magnets might even make it impossible to remove steel freight containers from the hold.
Now Martin Verweij and Erik Fiktorie of Delft University of Technology in the Netherlands claim to have developed an electromagnet that generates a magnetic field that does not penetrate too far into the ship.
Each of their mooring magnets generates a 1-tesla magnetic field. The magnets are formed from 13 long, thin, rod-shaped electromagnets placed side by side in a pattern that concentrates the magnetic field around the sides of the rods. The proximity of the rods ensures the field from each is attracted to its neighbours, rather than extending forward very far, the inventors say. They are confident their magnets will not affect anything inside a ship.
Verweij calculates that 52 of these magnets mounted along a quayside will be capable of holding a 400-metre container ship in place. The magnets are strong enough to secure a ship in winds of up to storm force 12, and will be unaffected by the wash from passing ships.
To allow the ship to rise and fall with the tide, the magnets are periodically switched off and then on again. This will happen too fast for the ship to drift out of range. A key part of the Rotterdam trial will be to see if this idea works.
A rival system being developed by Peter Montgomery of the company Mooring Systems in Christchurch, New Zealand, uses shore-mounted vacuum pods that cling to the side of a vessel. This system is almost entirely mechanical, using electric power only to attach the pods to the vessel.
Montgomery points out that the Dutch magnetic system will use a lot of electricity and may be prone to power failures. But Verweij counters that standby generators could guard against any power failures. And he says the magnets are much smaller than the vacuum pods, which he maintains would be an advantage in a busy container port.
But for the tests in Rotterdam, the engineers are playing safe. To back up the magnets, they will have mooring ropes to hand.
© Copyright Reed Business Information Ltd.
10:07 17 January 03
The magnetic wharf
Concentrated field
10:07 17 January 03
And there's the danger
that the Philadelphia
Experiment was
real, and these magnets
will transport the metal ships
through time and through space!
Probably not a good candidate for a dockworker.
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