Question 342General Subjects - Assistant Engineer

The correct answer is D) Line shaft bearings are generally lubricated by oiling rings or discs. This is the correct answer because line shaft bearings on marine vessels are typically lubricated using oiling rings or discs that dip into an oil bath and transfer the lubricating oil to the bearing surfaces. This method provides a consistent and reliable lubrication for the rotating line shaft without requiring a force-feed or gravity-based system. The other options are incorrect because wick lubrication, force-feed lubrication, and gravity feed lubrication are not the typical methods used for line shaft bearings on marine vessels. These alternative lubrication methods may be used in other applications, but they are not the standard practice for the lubrication of line shaft bearings on ships and boats.