Page 43: of Maritime Reporter Magazine (March 2001)

Coatings & Corrosion Control

Double Tro^ TrouWe,

The U.S. was instrumental in the introduction on a large scale of double-hulled tankers. Born out of a desire to make tanker vessels safer by making them more resilient in the event of a grounding or collision, double-hull designs nonetheless have corrosion proper- ties that legislators did not foresee. Double-hulled car- riers quickly proved themselves far more susceptible to internal corrosion than their single-hulled predeces- sors. Coatings manufacturers are now working hard towards a solution, according to one leading coatings specialist. "When the first generation of double-hulled tankers were taken into service, their owners were startled to find that their state-of-the-art ships were rotting away almost twice as quickly as sin- gle-hulled tankers. Pitting corrosion in the inner tank top plating was taking place at an annual rate of between 1 mm and 2 mm. In some instances, pits developed as deep as 7 mm to 9 mm within five years. That's 40 percent of the original plat- ing thickness," says Ed Jansen of Antwerp-based

Expertise- en Ingenieursbureau Touw-Jansen, a fOmniTHRUSTER 3EADOUi

Mixed-Flow Impeller

PATENTED SYSTEM ' Kinetic Converter takes input shaft energy and produces usable hydraulic energy by the use of a mixed flow impeller • Steering Vanes continu- ously meter or proportion a percentage of the fluid flow to one or both sides of the vessel . Nozzles accelerate the mass of water creating a thrust force at the hull interface • Thrust Directors (optional) deflect the water flow forward or aft producing slow speed auxiliary propulsion • Electronic Control System controls the 360° thrust vector resultant from a fixed or variable speed prime mover rotating continuously in one direction. . There are no rotating parts that have to be stopped or started as thrust direction and/or magnitude changes. •

J'L i .

Hl V* M m v 30555 Solon Industrial Parkway • Cleveland, OH 440 542-0200 www.omniWruster.com

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Ballast tanks are normally damp.

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March, 2001 www.maritimetoday.com Circle 328 on Reader Service Card 43