The mandate presents operators with a number of decisions. Because low-sulfur fuels will cost more, observers predict ships will elect to use them only where required, while continuing to burn high-sulfur oil elsewhere. Of course, this brings a need to carry two types of fuel and the incumbent logistical complications. As an alternative, MARPOL allows ships to reduce air emissions by installing scrubbers. A few technologies came to market recently, but the industry has not yet had time to develop a track record with them.

Observers say many operators have also worried they might need new diesel cylinder lubricants to use in conjunction with low-sulfur fuels. DCLs are total loss lubricants mixed with fuel feed to help protect cylinders and piston rings. They also account for most of the lubricant volume used on ships.

One of the main tasks for DCLs is to protect against acid corrosion – by far the biggest cause of cylinder wear, according to a presentation given by Kjeld Aabo, senior manager of engine manufacturer Man B&W Diesel AG, during BPs Winds of Change conference in Singapore in March. That corrosion results from the relatively high levels of sulfur trioxide created by burning of high-sulfur fuel. The industry has combated it by using highly alkaline DCLs; the typical product has a base number of 70.

But Man B&W, which is based in Augsburg, Germany, noted that operators do not want to eliminate acid altogether because doing so could polish cylinder liner surfaces, damaging the lubricant oil film and increasing the risk of scuffing. Consequently, marine lubricant suppliers have developed DCLs with base numbers ranging from 40 to 50 that are better suited for low-sulfur fuels.

This raises the potential scenario of ships carrying two types of DCLs, as well as two types of fuels, and also raises questions about how to store and feed the lubricants so as to prevent them from mixing and ensure proper feed rates.

Fortunately, most ships probably will not have to confront such a scenario – at least for a few more years. That was the conclusion of Aabos presentation – a copy of which was provided to Lube Report – and of another given at the Winds of Change conference by BP Marine Lubricants Managing Director Jill Nguyen. As a rule of thumb, Aabo said, DCLs with base numbers of either 70 or 40/50 are appropriate when using sulfur contents of 1 percent to 1.5 percent. Lubricant base numbers of 40 to 50 are more appropriate for lower sulfur levels, he said, but even here operators could probably continue using base number 70 lubricant when the vessel runs on low-sulfur fuel for a week or less. Highly alkaline lubricants are definitely needed for sulfur levels above 1.5 percent.

BP said the shipping industry in general has made the situation easier for itself by optimizing DCL feed rates – that is, restricting the rate of feed and therefore the alkalinity of the fuel-lubricant mixture.

Today, many operators have optimized their feed-rate to suit their maintenance plan, their engine component life, etc., the company said last week in response to follow-up questions by Lube Report. As a result, many ships are already on optimized feed-rate and not highly over-lubricated. Where ships are already optimized, the suggestion is to continue as normal. The key message is to avoid operating on excessive over-lubrication.

Those comments were echoed by Vince Kyle, vice president of marine lubricants for Chevrons Fuel and Marine Marketing LLC, who gave a presentation on marine lubricants at the ICIS World Base Oils Conference in London in February.

Im sure thats a relief to operators, said Charles Ashley Jr., executive director of the Deep Draft Lubricant Association, a Willis, Texas-based group of marine lubricant marketers and distributors. Using two types of lubricants would be a lot more complicated than carrying two kinds of fuel.

Man B&W, though, stressed the need to inspect engines to see how they perform.

[I]t is important to evaluate the engines actual condition after the first operating period on low-sulfur fuel, Aabo.

Observers allowed that the situation could become more complicated when fuel sulfur limits are tightened later this decade. The new low-sulfur limits are expected to extend to territorial waters of the rest of Western Europe and the United States, as well as the Mediterranean Sea. Moreover, the European Union is considering adopting a cap of 0.5 percent in 2008 and a ceiling of 0.1 percent is already scheduled to take effect in its ports at the end of 2009.

Kyle said it is too early to predict whether ship operators will have to change DCLs or lubrication practices at that time. BP declined to speculate what steps may be needed.

We will have suitable product to fill the market demand, and our guideline will be released at the appropriate time, the company said.