Bearings, lubrication, and care of machine parts

46 CFR §56.50-80

§ 56.50-80 -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 engi…

46 CFR §61.20-17

§ 61.20-17 -17 Examination intervals. (a) A lubricant that demonstrates the corrosion inhibiting properties of oil when tested in accordance with ASTM D665 (incorporated by reference, see § 61.03-1) is considered to be equivalent to oil for the purposes of the tailshaft examination interval. (b) Except as provided in paragraphs (c) through (f) of this section, each tailshaft on a vessel must be examined twice within any 5-year period. No more than 3 years may elapse between any 2 tailshaft examinations. (c) Tailshafts on vessels fitted with multiple shafts must be examined once every 5 years. (d) Tailshafts with inaccessible portions fabricated of materials resistant to corrosion by sea water, or fitted with a continuous liner or a sealing gland which prevents sea water from contacting…

46 CFR §61.20-23

§ 61.20-23 -23 Tailshaft clearance; bearing weardown. (a) Water lubricated bearings, other than rubber, must be rebushed as follows: (1) Where the propelling machinery is located amidship, the after stern tube bearing must be rebushed when it is worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the propelling machinery is located aft, the after stern tube bearing must be rebushed when weardown is 1.6 mm (.0625 in) less than the applicable clearance for propelling machinery located amidship. (b) Water lubricated rubber bearings must be rebushed when…

DOE-HDBK-1018 Vol.1 §1-4

DOE-HDBK-1018 Vol.1 §1-4 — Cooling and lubrication support systems Combustion temperatures far exceed the melting point of engine metals, so a cooling system must carry away roughly a third of the fuel's heat energy to keep cylinder liners, heads, and valves within safe limits while holding the block warm enough for efficient combustion. Most marine diesels use a closed jacket-water (fresh-water) loop circulated by an engine-driven centrifugal pump through the block, heads, and a heat exchanger; that jacket water is in turn cooled by raw seawater in a shell-and-tube or plate cooler. A thermostat regulates temperature by bypassing the cooler until the engine is warm. Too-cold operation causes incomplete combustion and cylinder wash-down; overheating causes loss of oil film, scoring, and cr…

NAVEDTRA 14075 §3-3

NAVEDTRA 14075 §3-3 — Lubricating-oil systems The lubricating-oil system reduces friction and wear, cools the moving parts, carries away metal and combustion debris, cushions bearing shock loads, and helps seal the piston rings. In a typical wet-sump engine, a gear pump draws oil from the sump through a suction strainer and delivers it under pressure through a full-flow filter and a lube-oil cooler to the main bearings, connecting-rod bearings, camshaft, valve gear, and — through drilled passages or spray nozzles — to the underside of the piston crowns for cooling. A relief valve holds system pressure and a bypass allows oil to keep flowing if the filter or cooler becomes restricted. Large engines use a dry-sump system with a separate lube-oil tank and both pressure and scavenge pumps. Oi…

NAVEDTRA 14075 §3-4

NAVEDTRA 14075 §3-4 — Lube-oil and fuel-oil purifiers (centrifuges) A purifier is a high-speed centrifuge that continuously cleans lube oil and heavy fuel oil by spinning it fast enough to throw out the denser contaminants — water and solid sludge — that gravity settling alone cannot remove in reasonable time. Inside the bowl a stack of closely spaced conical discs divides the oil into thin layers and forces separation to happen over a very short radial distance: the heavy water and solids move outward to the bowl wall while the clean, lighter oil moves inward and is discharged. Because the centrifugal force in the bowl is thousands of times gravity, separation that would take hours in a settling tank happens in seconds of dwell time. A centrifuge run as a purifier separates water as well…