Commercial Vessel Compliance

12/16/2016: Safety alert – MAN B&W Cooling Jacket Failures

The Coast Guard published Marine Safety Advisory 17-16 to bring attention to a problem with cracks on the cooling jacket.

Recently, a 738-foot bulk carrier ran aground while outbound on the Columbia River. The grounding resulted in limited damage to the vessel and no pollution or loss of cargo. This casualty occurred primarily because of cracks on the cooling jacket of a two-stroke crosshead design Mitsui MAN B&W MC-C engine. The cracks caused a loss of engine cooling water that eventually resulted in the overheating of the cylinder cover. This then triggered an automated slow-down of the engine and an unintended loss or reduction in the vessel’s propulsion and maneuverability.

The cooling jacket is normally held in place by the use of four shoulder type bolts that go through the cooling jacket and into the sides of the cylinder cover. Please watch the following YouTube videos for more information: Video A and Video B.

MAN B&W has developed a Service Letter related to this issue and it is available here.

As a result of these casualties the Coast Guard strongly recommends, regardless of engine manufacturer, that:

  • Owners, managers and operators ensure that their vessel engineering staffs have access to all available manufacturer service letters for propulsion, electrical generation, steering and other critical equipment; and
  • Senior engineering personnel on vessels with MAN B&W MC-C and other similarly constructed engines using the same cooling jacket cover securing method review the applicable maintenance procedures and ensure that persons assembling these components know that the shoulder bolts may not butt up against the cooling jacket cover, as breakage may occur if forced, and that regular bolts with no shoulders should never be used.


Read Marine Safety Advisory 17-16 for full details.

This safety alert is provided for informational purpose only and does not relieve any domestic or international safety, operational, or material requirements. Developed by the Investigations Division of Marine Safety Unit Portland, Oregon and the Coast Guard Headquarters Office of Investigations and Casualty Analysis. Questions or comments may be sent to

This blog is not a replacement or substitute for the formal posting of regulations and updates or existing processes for receiving formal feedback of the same. Links provided on this blog will direct the reader to official source documents, such as the Federal Register, Homeport and the Code of Federal Regulations. These documents remain the official source for regulatory information published by the Coast Guard.

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