Study Shows Slow Steaming Doesn't Hurt Engines

Slow steaming, a practice that ocean carriers adopted during the last four years to save on bunker fuel costs, is likely to become even more common now that a study by Maersk Line shows that low speeds do not damage engines.

Maersk vessels sustained zero damage from slowing since the Danish shipping line began lowering speeds to cut fuel costs in 2007, Jan de Kat, Maersk senior technical adviser, told Bloomberg. On the contrary, Maersk’s operating expenses declined as a result of the practice because it placed less strain on the engines, so they required less maintenance.

“If you look at average speeds, we think they will be slower,” de Kat said. “There were a lot of concerns about soot build-up, vibrations and propeller health. We addressed those concerns and found solutions.”

The most economical speed for container ships is 10 to 15 knots instead of the standard 25 knots, according to the company, which has a fleet of about 500 vessels, de Kat said. Maersk is sharing its data with engine manufacturers and other ship owners to show ways to overcome technical concerns about slower speeds.

Maersk backs voluntary slow-steaming rather than regulation so shipowners can retain the flexibility to keep shipments on schedule.

The company said its findings apply to any ship propelled by a two-stroke engine, the most common type for tankers, container ships and bulk carriers. Maersk said its own fleet has reached its lower limit and won’t slow further.

The average speed of all vessels has fallen about 27 percent since July 2008, when average daily earnings were 3.6 percent higher than today, according to data from Bloomberg and Clarksons, the world’s largest shipbroker. As global demand sank and fleets swelled, shipowners reduced speeds to boost earnings by saving on fuel.

Nearly all of Maersk’s container ships, and now some of its tankers, have operated at 10 percent of maximum power since January 2009, according to de Kat. The company said the engines have not suffered any damage as a result and its fuel savings average about 7 percent.

-- Contact Peter T. Leach at pleach@joc.com. Follow him on Twitter @petertleach.