Ballast-free Ships

Posted on March 25, 2008  Comments (2)

ballast-free ship’ could cut costs while blocking aquatic invaders

University of Michigan researchers are investigating a radical new design for cargo ships that would eliminate ballast tanks, the water-filled compartments that enable non-native creatures to sneak into the Great Lakes from overseas. At least 185 non-native aquatic species have been identified in the Great Lakes, and ballast water is blamed for the introduction of most—including the notorious zebra and quagga mussels and two species of gobies.

This week, the U.S. Saint Lawrence Seaway Development Corp. will implement new rules designed to reduce Great Lakes invaders. Ships will be required to flush ballast tanks with salt water before entering the Seaway, a practice corporation officials describe as an interim measure, not a final solution.

Instead of hauling potentially contaminated water across the ocean, then dumping it in a Great Lakes port, a ballast-free ship would create a constant flow of local seawater through a network of large pipes, called trunks, that runs from the bow to the stern, below the waterline.

“In some ways, it’s more like a submarine than a surface ship,” Parsons said. “We’re opening part of the hull to the sea, creating a very slow flow through the trunks from bow to stern.

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2 Responses to “Ballast-free Ships”

  1. John Alford
    July 14th, 2008 @ 11:54 am

    I can understand the need to avoid the transference of contaminated water. What I don’t quite understand is why the transference of ‘non-native’ aquatic species is such a bad thing.

    Or is it the case that because the water’s contaminated, the aquatic species are contaminated too?

  2. Curious Cat Science and Engineering Blog » 2 Mysterious Species in the UK
    July 15th, 2008 @ 8:34 pm

    “This mystery bug has not been seen in the UK before and has made the Natural History Museum’s Wildlife Garden its home…”

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