Stern tube bearings are generally lubricated by gravity feed systems or an electric driven pump or pump driven by a cam attached to the intermediate shaft. In tank system, it is placed at sufficient height to give sufficient heard to force lubricant into the bearing at all times. A pipe leads from the tank to the top of the s/t tube through the aft peak bulkhead. and a pipe run parallel to the supply pipe and return back to the gravity tank. There are temperature sensors also. the minimum bearing length must be twice that of shaft diameter.
bearing clearance should not be exceeded more than .2mm. the oil pressure is maintained approximately same as that of surrounding sea water. oil is contained inside the stern tube by lip seals. The bush is made up of grey or nodular cast iron centrifugally lined with cast iron. The elastic lip of each Nitrile rubber seal grips a rubbing surface provided by short chrome steel liners at outboard and inboard ends of the shaft.
bearing clearance should not be exceeded more than .2mm. the oil pressure is maintained approximately same as that of surrounding sea water. oil is contained inside the stern tube by lip seals. The bush is made up of grey or nodular cast iron centrifugally lined with cast iron. The elastic lip of each Nitrile rubber seal grips a rubbing surface provided by short chrome steel liners at outboard and inboard ends of the shaft.
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