Wheelabrator Abrasives
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- Double Trouble? Double Trouble? Maritime Reporter, Mar 2001 #43
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 properties that legislators did not foresee. Double-hulled carriers quickly proved themselves far more susceptible to internal corrosion than their single-hulled predecessors.
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 single- 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 plating thickness," says Ed Jansen of Antwerp-based Expertise- en Ingenieursbureau Touw-Jansen, a specialist marine consultancy firm.
This came as a shock to the system to an industry that had been used to doing major corrosion repair work around the time of the second special survey.
Suddenly, owners found that they were footing hefty repair bills on very young ships. But why were double-hulled tankers rusting away so quickly?
The answer was provided only recently, thanks to work done by Sigma Coatings, for whom Jansen acts as a consultant.
"Research done by Rodney Towers at Sigma suggests that the corrosion problems caused on board double-hulled tankers can be attributed to the thermos- flask effect of the design. Crude oil is usually loaded in locations where temperatures can reach as high as 45 to 50 degrees Celsius. It is then shipped to locations that are much cooler. If it is carried on board single-hulled ships, the oil cools down comparatively quickly under the influence of the ambient sea temperature, reaching sea temperature between 36 and 48 hours after being loaded, depending on the volume of oil and other factors.
On board double-hulled vessels, cooling down times are much longer, taking days rather than hours," Jansen explains. Oil in double-hulled tanks takes an average of 20 days to reach sea temperature, he adds.
The significance of the longer cooling down period is found in the lifecycle of corrosion inducing bacteria. The bacteria survive longer in the warmer oil in double-hulled ships, lengthening the electrochemical corrosion process that naturally occurs at the bottom of cargo tanks on board oil carriers.
Not only do the bottom of tanks on board doublehulled vessels rust more rapidly, under-deck plating and ullage areas are more prone to corrosion as well. The reason for this is a different one, however.
Here, it is the choice of construction material that is significant. To offset the increase in weight due to the extra steel required for double-hulled newbuilds, shipyards incorporated higher levels of high-tensile steel into their designs. "High-tensile steel ships are subject to greater degrees of hull flexing at sea. This is important when you consider the corrosive processes in under-deck and ullage spaces," Jansen says. During ballast voyages, inert gas is pumped into the cargo tanks of tankers to prevent the build up of flammable gases from cargo residues. Inert gas is also used to fill up the ullage space left after a cargo has been loaded. The gas used is generally pumped in at a temperature of roughly 45 degrees Celsius.
At night, the natural drop in temperature will cause the gas to cool to around 20 degrees Celsius.
Even the thermos-flask characteristics of a doublehulled ship cannot prevent this. As a result, the walls lining the spaces filled with gas are covered in condensation.
Rodney Towers' study suggests that in an inerted VLCC as much as 12 tons of condensation can be created each night. "The condensation dissolves solubles in the inert gas mixture that trigger the corrosion process," Jansen explains.
This is particularly damaging for ships with high levels of high-tensile steel. Their increased flexing during voyages leads to higher levels of flaking. Flaking exposes fresh areas of steel for the corrosive solubles to do their damage. According to Jansen, "By encouraging flaking, high-tensile steel is its own worst enemy." The good news for owners is that coatings manufacturers have been hard at work to develop products that will help prevent excessive corrosion. Rodney Towers' work has been very significant and Sigma Coatings is addressing the issues raised by his research. Jansen will be helping the company better understand the requirements of modern tanker shipping. "Improved coatings, a clearer understanding of coatings on the part of crews, and investment in coatings by owners at the newbuild stage will help prevent double-hulled tankers from causing more problems than they solve," he says.
Wheelabrator Elects N e w Sales Manager Wheelabrator Abrasives, Atlanta, Ga., has named Christopher Pawlicki as the regional sales manager for Ohio, the Northeastern U.S. and Ontario, Canada.
Pawlicki, who has an extensive background in industrial sales, most recently served as a manufacturer's representative for various quality products.
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April 2024 - Marine News page: 39There are ? ve major paint catego- lenges in shipyards is managing small building is a multifaceted endeavor ries in new construction shipbuilding: parts, which are prone to surface rust that demands integrative systems before installation. Optimizing the planning, as well as adoption of new 1.
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January 2024 - Maritime Reporter and Engineering News page: 20TECH FEATURE Figure 4. The vessel’s cargo holds feature Figure 5. The walls of the cargo holds All images courtesy of The Interlake Steamship Company ? at bottoms that accommodate the use bene? t from a zinc-based coating that of heavy machinery, which necessitated provides durability in an area
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August 2023 - Maritime Reporter and Engineering News page: 56Tech Files Tools L.S. Starrett Saint-Gobain Abrasives Weiler Tiger 2.0 Cutting, Grinding TENNAX-PRO Saw Blades "Norton for Aluminum" Weiler Abrasives debuts the Tiger 2.0 L.S. Starrett Co. introduced TEN- Saint-Gobain Abrasives introduced zirconia alumina and aluminum oxide NAX-PRO Bi-Metal Band Saw
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August 2023 - Marine News page: 42Tech File Shipyard Tools jects of rust, paint and contaminants to bare metal. lando, Fla.-based Laser Photonics, a provider of patented However, for operators, exposure to corrosive acids and industrial grade CleanTech laser systems for cleaning and noxious chemical fumes is inherently dangerous.
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August 2023 - Marine News page: 41al laser systems are increasingly being used at shipyards, million U.S. workers are at risk of developing silicosis shipbuilding berths and even aboard ships. Technicians and that more than 100,000 of these workers are em- can use mobile handheld units, or if needed the systems ployed as sandblasters.
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August 2022 - Maritime Reporter and Engineering News page: 59Tech Files The month’s best technical innovations Moteurs Baudouin CorrVerter for Rusty Surface Prep D13 Expands IMO Tier III Range The 6F21 Volvo Penta has expanded its marine Moteurs Baudouin has designed the Sandblasting, water blasting, and IMO Tier III range with new D13 solu- new 6-cylinder 6F21
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April 2022 - Maritime Reporter and Engineering News page: 16Fire Safety NFPA Certi? cated Marine Chemists – A Century of Fire Protection and Life Safety By Lawrence B. Russell and Guy R. Colonna, P.E. Courtesy NFPA try representatives including the American Bureau of Ship- ping (ABS) asked NFPA for assistance in the development of a ? re prevention standard
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September 2021 - Maritime Reporter and Engineering News page: 58Tech Files Innovative products, technologies and concepts Su-Nav Rolls our Clean Water Tech to Fleet Su-Nav, an integrated ship management com- pany, has rolled out the latest sustainable, green product from its Su-Nav Aeronero Innovation Center which will provide thousands of seafar- ers with pure
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August 2021 - Maritime Reporter and Engineering News page: 56Tech Files Shipyard Tools SubArc Digital Converter Part of a Norton BlueFire Abrasives ICR Technowrap, Quick? ange Complete Digital Solution Saint-Gobain Abrasives introduced ICR Integrity (ICR) won a three-year Miller Electric expanded its digital upgraded Norton BlueFire Abrasives contract with
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June 2021 - Maritime Reporter and Engineering News page: 50TECH FEATURE BIOFOULING Figure 1: Static biofouling growth of Hard Foul Release (white panel), polyvinyl chloride (PVC) negative control, and a soft foul release coating. Figure 2: Fouling rate comparison of XGIT-Fuel, PVC, and Soft Foul Release. This table shows a comparative analysis of the leading
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June 2021 - Maritime Reporter and Engineering News page: 49TECH FEATURE BIOFOULING ernative for Biofouling Control not to clean their hulls even when a or in drydock for an in-service vessel. the bene? ts of a hard cleanable surface heavy layer of slime has built up. Heavy However, these coatings offer no anti- while obtaining signi? cant fuel savings slime
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November 2020 - Marine News page: 73PRODUCTS FleetManager 4.0 C-MAP calls FleetManager 4.0 its “most impressive web-based ? eet management solution to date”. A decade from the launch of the ? rst LogCentral ever FleetManager, this new version OneOcean’s LogCentral is a digital incorporates an all-new, lightning- tool with an
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January 2020 - Marine News page: 60PRODUCTS Telescopic Rescue Poles Seeing the need for a swift and accu- rate recovery method should a person fall into the water, the team at Sham- rock Quay in Southampton – part Norton Rapid Prep XHD of MDL Marinas Group – acquired KINETIX Coarse and Medium Discs a Reach and Rescue telescopic
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September 2019 - Marine News page: 58PRODUCTS SPD-Smartglass Dimmable Windows for Passenger Vessels Passengers marvel at magni? cent seaside views, but can be uncomfort- able with too much sunlight, glare and heat. Vision Systems’ SPD- SmartGlass products are designed Ship Propeller Cleaning Chopper Pumps solve for the cruise
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August 2019 - Maritime Reporter and Engineering News page: 68P PRODUCTS SHIPBUILDING TOOLS HGG Ship Pro? ler HGG’S new UPC 450 Ship Pro? ler increases cut- ting and pre-fabrication productivity by eliminat- ing the need to cut ship stiffeners and spools by hand. HGG production automation combines ship stiffener cutting, 3D pro? le cutting with optional tube
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August 2019 - Marine News page: 84MN100 Michael L. Lapeyrouse, CEO/President THE AMERICAN EQUITY UNDERWRITERS, INC. The Case: Nearly 1,300 waterfront employers trust the experts THORDON BEARINGS INC. at The American Equity Underwriters, Inc. with their longshore workers’ compensation needs. AEU has care- The Case: fully built services
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May 2019 - Maritime Reporter and Engineering News page: 70T TECH FILES ALFA LAVAL Sanmar, CAT: Hybrid Collaboration PUREBALLAST 3 Alfa Laval PureBallast 3 Sanmar Shipyards was selected by received an updated type ap- Caterpillar Marine to build the ? rst proval from the U.S. Coast tug to incorporate its hydraulic hybrid Guard. Alfa Laval PureBallast propulsi
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April 2019 - Marine News page: 40COATINGS/CORROSION CONTROL Green Shipyard Coatings: Green is the Best Color VT Halter’s new state-of-the-art blast and paint facility, already paying dividends for the shipyard’s bottom line and the environment alike, is poised to lif your bottom line with improved coatings and reduced corrosion. By
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March 2019 - Maritime Reporter and Engineering News page: 23SPECIAL ADVERTISING SECTION Coat with Con? dence HoldTight’s family of surface prep products works to ensure the integrity of your vessel’s coating system While much maritime press focuses on ‘autonomy’ and within minutes. They found conventional rust inhibitors be applied to blasted surfaces, preserving
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January 2019 - Maritime Reporter and Engineering News page: 49Case Study Dole & Talusia Optima Following the introduction of the 0.1% sulfur cap imposed within ECAs off the U.S. coast in 2015, Dole realized it had a problem. The engines of two of its vessels, ‘Dole Chile’ and ‘Dole Columbia’, which had been transporting fresh fruit from South to North America for
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November 2018 - Marine News page: 85must be detailed in a written control plan, which should include speci? c tasks and those responsible for imple- menting the changes to help reduce exposure to the employees. Of equal importance, all workers must receive training on operations that result in silica exposure as well as ways to limit
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November 2018 - Marine News page: 84COLUMN SAFETY Maritime Industry Faces Compliance Standard from OSHA on Respirable Crystalline Silica Companies with workers repairing and refurbishing ship components utilizing sand blasting have become the subject of a new U.S. Department of Labor Occupational Safety and Health Administration (OSHA)
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October 2018 - Maritime Reporter and Engineering News page: 81COATINGS & CORROSION CONTROL Poly? ake Coatings Protection against chemical, mechanical and galvanic corrosion. By Lisa Overing Corrosion starts from the inside out. The alkali that metallurgical tests and it was all 5083, 5086 good discharge line to protect the carbon steel piping with neutralizes
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September 2018 - Maritime Reporter and Engineering News page: 54CUTTING & WELDING have become popular because material ishing problems with brushing technol- Widely known by the handling is costly. Shipyards can save ogy in the sophisticated environments of brand name Flex- a lot of money if their cutting systems nuclear energy, aerospace and computer Hone, the