[BITList] Lloyd's List: Send to Colleague

Tue Dec 9 09:38:36 GMT 2008

The below article was sent to you from Mike Feltham (mj.feltham at madasafish.com) with the following message: I thought you might be interested in the article below.

Sign up to the FREE Lloyd's List Daily News Bulletin at http://www.lloydslist.com/bulletin

Slow speed ahead as owners request engine modification
Tuesday 9 December 2008

WITH the hike in fuel prices earlier in the summer and the economic downturn affecting rates, increasing numbers of owners have been turning to their engine makers to have overpowered engines adapted for slower steaming.
During the boom years, many vessels were built with overpowered two-stroke engines with multiple turbochargers as the market demanded high steaming speeds. 
But now both MAN Diesel and Wärtsilä have reported a surge in interest from owners looking to make permanent adaptations to allow their engines to have more versatility and operate better at different speeds. 
They say that all major shipowners have sought quotes for adapting engines to have the versatility to run at slower speeds indefinitely, after many years of putting speed and power before fuel consumption figures.
&#8220;For a long period we have been selling engines with as much power as possible,&#8221; said MAN Diesel senior vice-president Otto Winkel, who said owners have two choices. 
&#8220;One is to derate, which is a permanent reduction of maximum continuous output; the other is to optimise part load, such as cutting out a turbocharger.&#8221;
Derating means changing the turbocharger and compression ratio in the engine so that at a lower power you reach the peak pressure in the cylinder and therefore obtain lower specific fuel consumption. Derating, however, could mean a change in NOx emissions and therefore re-certification.
One option being promoted by Wärtsilä is its slow steaming kit, applicable for high-speed two-stroke engines with two or more turbochargers. 
One of the first owners to install an adaptation kit is German containership owner Koepping Shipping. The company approached Wärtsilä regarding the 1,200 teu fast feeder containership Aglaia, bought earlier in the year.
The seven-year-old 14,278 gt vessel is powered with a single eight-cylinder RTA62A Wärtsilä engine operating at 113rpm, with two Sulzer turbochargers.
The solution is simple, providing the ship&#8217;s engineers with the possibility to switch off a turbocharger. This effectively maintains scavenge air pressure when the engine is running at lower loads and ensures the engine performs well, but also provides the required reduction in fuel consumption.
Koepping senior technical superintendent Michael Niessl said that under normal arrangements the Wärtsilä engine on the Aglaia was capable of running at slower speeds, but only to about 40% load.
&#8220;The only thing then is that you increase your fouling in the exhaust gas system, which means you have to speed up the engine twice a day for about an hour to eliminate it,&#8221; he said. 
The adaptation using the slow steaming kit being promoted by the engine maker will give the ability to reduce load to 20% without experiencing such problems.
At normal load the vessel has an operating speed of 22 knots, with the main engine running at a service output of 15,100 kW. Fuel consumption is approximately 66 tonnes of intermediate fuel oil.
With normal slow steaming at 40% load, the vessel achieves 19 knots, consuming 41 tonnes of fuel.
The ability to switch off one of the two turbochargers will allow the load to come down as low as 20% if needed, although Koepping anticipates 15.8 knots with fuel consumption down to 25 tonnes at 35% load, but without the fouling.
Wärtsilä said that application of its slow steaming kit took a few weeks, as after the first pre-inspection the material was tailor-made before being brought onboard the vessel for installation by its engineers. 
This took a couple of days to complete and could be done without the vessel being taken off-hire.
&#8220;They need to find the best position for the shut-off valves for the turbocharger, and in addition the engine needs to be equipped with a pulse lubrication system, as common lubrication at such low load will over-lubricate the cylinder liner,&#8221; said Koepping Shipping&#8217;s Niessl, who believes the whole process for this first vessel could take a bit longer.
The vessel will also have a torsion meter and updated control systems installed. The work should be completed in February next year.
If the conversion goes well, Koepping Shipping expects to apply the same changes to another of its vessels that has an overpowered two-stroke engine with multiple turbochargers.
The majority of its fleet, though, are fitted with MAN Diesel engines and single turbochargers, which Mr Niessl said could be fitted with adjustable nozzle rings to enhance performance.
The ability to reduce the number of turbochargers in operation on vessels with more than one fitted does not come as standard with either MAN Diesel or Wärtsilä engines. 
Wärtsilä has said that the electronically controlled lubricating system is a standard feature for newly ordered portfolio engines, subject to the specification being made when the engines are ordered. It said that waste gates have also been made available.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.bcn.mythic-beasts.com/pipermail/bitlist/attachments/20081209/85999d21/attachment-0001.shtml 