Section 56.50-80 - Lubricating-oil systems(a) The lubricating oil system must be designed to function satisfactorily when the vessel has a permanent 15° list and a permanent 5° trim. See § 58.01-40 of this subchapter for operational requirements for propulsion and vital machinery at vessel angles of inclination.(b) When pressure or gravity-forced lubrication is employed for the main propelling machinery, an independent auxiliary lubricating pump must be provided.(c) Oil coolers must be provided with two separate means of circulating water through the coolers.(d) For internal combustion engine installations, the requirements of paragraphs (b) and (c) of this section do not apply to vessels in river and harbor service, nor to any vessel below 300 gross tons. For internal combustion engines, two separate means are to be provided for circulating coolant. One of those means must be independently driven and may consist of a connection from a pump of adequate size normally used for other purposes utilizing the required coolant. Oil filters must be provided on all internal combustion engine installations. On main propulsion engines fitted with full-flow type filters, the arrangement must be such that the filters may be cleaned without interrupting the oil supply except that such an arrangement is not required on vessels having more than one main propulsion engine.(e) The lubricating oil piping must be independent of other piping systems and must be provided with necessary coolers, heaters, filters, etc., for proper operation. Oil heaters must be fitted with bypasses.(f) Diesel engine lubrication systems must be so arranged that vapors from the sump tank may not be discharged back into the engine crank case of engines of the dry sump type.(g) Steam turbine driven propulsion and auxiliary generating machinery depending on forced lubrication must be arranged to shut down automatically upon failure of the lubricating system.(h) Sight-flow glasses may be used in lubricating-oil systems provided they can withstand exposure to a flame at a temperature of 927 °C (1,700 °F) for one hour, without appreciable leakage.(i) Steam driven propulsion machinery must be provided with an emergency supply of lubricating oil that must operate automatically upon failure of the lubricating oil system. The emergency oil supply must be adequate to provide lubrication until the equipment comes to rest during automatic shutdown.CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69-127, 35 FR 9979, June 17, 1970; CGD 81-030, 53 FR 17837, May 18, 1988; CGD 83-043, 60 FR 24774, May 10, 1995