Suppose a water-lubricated stern tube bearing is being evaluated for wear where the propulsion machinery is located amidship. If the tailshaft diameter is 10.5 inches, according to 46 CFR regulations pertaining to periodic tests and inspections as related to machinery and equipment, what would be the maximum clearance diameter permissible before the bearing must be re-bushed?

Question

Accepted Answer

Option C: 0.3125 inches. Under 46 CFR bearing wear limits for water-lubricated stern tubes, a 10.5-inch shaft permits a maximum allowable wear clearance of 0.3125 inches before mandatory bushing renewal.