Uncovered: Lax Coating Application, Maintenance Come At A High Cost
One Step At A Time With the increasing complexity of marine coatings, susceptibility to misuse has risen. Although modern systems demand greater vigilance in ensuring correct application and maintenance, problems subsequently encountered in service point to a lack of specific knowledge among shipyards, operators and crews.
Strict protocols now need to be observed in applying coatings, and every step of the process has to be recorded. "It's a precise and timeconsuming task, but such are today's commercial pressures that yards and shipowners sometimes feel the need to cut corners," said paints and coatings expert Ed Jansen, of Antwerp-based Touw- Jansen.
Any shortcomings in the quality of the preparation and application work, or any cutback on the original specification in order to speed newbuilding delivery or trim costs, will produce extra cost in the longer term. The coating will deteriorate quickly and start to blister, flake, crack or crocodile, requiring an expensive repaint.
Tank coatings are particularly sensitive to irregularities, and call for the highest standard of application. However, according to Mr.
Jansen, most problems with such coatings occur after a vessel has been delivered, due to carelessness or improper use. The slightest chip in a coating can lead to its eventual demise, and it is significant that deterioration frequently starts at a spot just below access points through which tools and equipment are fed down into the tank in the course of maintenance work. Non-adherence to the prescribed cargo range within the scope of the protection system can, and does, lead to major problems, particularly where the coating resistance list has not been passed on to shipmanagers and charterers.
Owners should also impress upon crews the importance of ventilation, suggested Mr. Jansen. "In a case not long ago, a complete fleet of chemical carriers had to be recoated when the crew failed to ventilate the cargo tanks properly after carrying methanol," he said. "Water-based cargoes were loaded too soon afterward and the residual methanol in the tank coatings drew water into the coatings, causing swelling and cracking. The whole fleet was out of service for several weeks and the total bill for re-coatings and off-hires topped an estimated $25 million." As an authority on the subject, Mr. Jansen takes the view that owners should spend as much time deciding on a paint system as on major machinery or equipment selection. And once a ship has entered service, every effort should be made to ensure that those operating the vessel understand the delicate nature of the tank coatings in particular.
(For the latest marine paints and coatings system offerings from manufacturers, please refer to this month's "Marine Coatings & Corrosion Control" section, which starts on page 58).
The New Thoroughbreds Medium-speed propulsion machinery of a new, thoroughbred type is set to make its debut in a new generation of North Sea RoRo ships intended to ensure faster, more efficient freight exchange between Sweden, the U.K. and Belgium.
In addition to the commercial significance conferred by an opening reference for the 500-mm bore, four-stroke design conceived in Winterthur, the fountainhead of Swiss diesel engineering, the project has a wider industrial aspect in the context of the rationalization taking place in the business in Europe.
The compact ZA50S perpetuates the Sulzer marque in the mediumspeed domain against a backcloth of the commanding presence of the companion Wartsila range in the four-stroke field. The emergence of the new Sulzer machine is of added note for the unmatched level of medium-speed product development steered from Finland by parent organization Wartsila NSD Corporation, to strengthen the market standing of the Wartsilabranded portfolio.
Work on the ZA50S, though, was set in train well before the combination of Wartsila Diesel with Fincantieri-owned New Sulzer Diesel, as an evolutionary progression of the ZA series, which has achieved considerable success in the ZA40S. The fact that the first three recipients of the ZA50S design — the trio of twin-screw, 8,700-dwt Tor Line newbuildings were ordered from Fincantieri, brought manufacture of the engines within the Italian group's remit.
In any event, the industrial philosophy espoused by Wartsila NSD's Finnish owners is reflected in the company's decision to concentrate all ZA production at the Grandi Motori Trieste (GMT) works, in which the Finnish group has a 40 percent stake. The ZA40S, for which 729 sales had been chalked-up in the marine and power plant sectors by December 1997, remains fully in the Wartsila NSD program, since there are many applications for which its power output and physical size are still very appropriate.
Wartsila NSD's 'focused factory' concept, as applied to the Sulzer medium-speed engines and the huge GMT complex at Trieste, signals the end of ZA40S manufacture as the mainstream activity at the Mantes works of New Sulzer Diesel France, which will become primarily a maker of parts.
Trieste has also been nominated as the production point for the Wartsila 64, the world's most powerful medium-speed engine, in addition to its substantial role as a manufacturer of Sulzer two-stroke engines.
The twin Sulzer 9ZA50S engines selected for each of the new Tor Line ships will have a combined maximum continuous rating of 29,340-bhp (21,600-kW) at 450 rpm, driving controllable pitch propellers, for a service speed of 21.1 knots. With its higher cylinder output, the ZA50S meets market requirements for higher installed powers with fewer cylinders, in the larger and also faster types of ships where machinery space is restricted.
Re-Focused Energies Skills crafted and honed in shipyards on naval contracts can be effectively re-deployed to foster commercial diversification, given committed and focused management. Faced with generally reduced naval defense expenditure in the west — bred of a political complacency over national security following the end of the Cold War — naval yards, ancillary sectors and workforces have suffered contraction above and beyond that which technological progress itself would have brought.
In the European scenario, establishments in Italy and Scotland visited by MR /EN in recent weeks provide examples of the successful re-deployment of skills and resources into growth markets, albeit without the same degree of capital and work-hour intensity associated with work on fighting ships.
On the Ligurian coast, Fincantieri's naval shipbuilding division is readying the world's largest monohull fast ferry for year-round service in the Sardinian traffic, following its launching at Riva Trigoso in January. The stern-ramped Tirrenia ferry, designed to carry 1,800 passengers and 460 cars at around 40 knots, encapsulates the rapid progression of the division in developing a position in the commercial market, and in driving the technology ever-forward. In more northerly climes, at one of Western Europe's largest naval support facilities, the precision engineering skills at Rosyth Royal Dockyard have been applied to effect in the offshore and rail sectors. The current output of subsea production manifolds, and the development of versatile new types of freight wagon for an increasingly integrated European rail network, give expression to the successful policy of Babcock International, as the new owner of the complex, to complement Rosyth's naval workload with other targeted business.