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#1
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Outboard thrust bearing for sailboat.
To me, this is a bit confusing??
Does your boat have an inboard engine with a propellor shaft?? or are you talking about an Outboard motor or Out drive?? A properly installed marine engine will have the thrust bearing in the reduction/reverse gear. If it is an OB or Out Drive, the thrust bearing is inside the lower unit. I've never heard of a thrust bearing at the propellor. There should only be a water lubricated cutlass bearing. Please provide more information on what you have, engine/rev. gear, etc. and maybe we can figure a solution. Steve s/v Good Intentions |
#2
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Outboard thrust bearing for sailboat.
"Steve" wrote in message ...
To me, this is a bit confusing?? Does your boat have an inboard engine with a propellor shaft?? or are you talking about an Outboard motor or Out drive?? A properly installed marine engine will have the thrust bearing in the reduction/reverse gear. If it is an OB or Out Drive, the thrust bearing is inside the lower unit. I've never heard of a thrust bearing at the propellor. There should only be a water lubricated cutlass bearing. Please provide more information on what you have, engine/rev. gear, etc. and maybe we can figure a solution. Steve s/v Good Intentions Here is a link that shows a diagram of the boat http://home.worldonline.dk/sejler/scampi/scampi.htm This boat has an hydraulic drive system. The brace that you see in front of the impeller is where the bearing should be ( I think) It looks like a very strong support made out of metal and imbedded in the fiberglass. |
#3
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Outboard thrust bearing for sailboat.
john m says:
This boat has an hydraulic drive system. Probably just a hydraulic gearbox, from the looks of things... The brace that you see in front of the impeller is where the bearing should be ( I think) It looks like a very strong support made out of metal and imbedded in the fiberglass. THat would be called the strut, and the bearing in it is just a cutlass bearing, Rubber in a metal tube. It is supposed to be like that, as it's only job is to support the shaft. The actual thrust bearing is inside the boat, usually either just aft of the transmission, or integral to the tranny. Steve |
#4
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Outboard thrust bearing for sailboat.
From what I see of your drawing, the fitting your discribe forward of the prop is a standard strut.. I doubt that your strut installation is made to take the full thrust of the propellor.. I agree with Matt. Conventions would have the thrust bearing in the hydrolic pump and only a cutlass bearing in the strut. I suspect someone has tried to 'Improve' the installation.. Or the hydraulic motor has a bad thrust bearing. If in doubt, contact the manufacture of the hydraulic motor and determine if the the motor has a thrust bearing in it.. If so then you need to verify that it is in good condition and leave the one you found out of the installation.. Or there is another possibility, that the original builders hydraulic motor went bad and some one put a conventional/industrial replacement in it's place. In this instance the industrial motor most likely wouldn't have a thrust bearing. Just my speculation, FWIW. Steve s/v Good Intentions |
#5
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Outboard thrust bearing for sailboat.
John,
Yes, I was contracted to repair the strut bedding when the boat got run with a damaged blade. That boat did not have the couple you describe between the hydralic motor and the prop shaft. There was also no conventional stuffing box. The prop shaft is enclosed in the stern tube from the after end of the strut into the hydralic motor. The motor is actually attached tot he stern tube and is supported by both that and a torque brace. After we got all of the other stuff fixed, the boat still would not make more than 4 knots and the engine was not loading. It back like a mad man. So the owner got another set of blades for the other rotation and shifted the pump to astern for ahead and now makes hull speed just fine. When I talked to him last he was trying to find someone that knew how to overhaul the pump and motor. When I see him next, I will ask him. A chain coupling in a drive shaft is rare and not a proper application. There is no way to put an axial load bearing (thrust) inside the stern tube, so it must be in the hydraulic motor. That is part of why the plastic washer is both installed and torn up. I suspect the washer is required to keep the coupling halves from wearing on each other. It is, however, not costing you horsepower. Bearings going bad can cause vibration and failures, but if they eat horsepower they burn up real fast. I suspect that if you are short on boat speed as you seem to say farther down the thread, you have hydraulic drive problems just like the Scampi I know had (may still). I would see about getting both the pump and motor looked at before you invest much effort in other paths. Good Luck Matt Colie - See Prior Sig john m. wrote: "Steve" wrote in message ... To me, this is a bit confusing?? Does your boat have an inboard engine with a propellor shaft?? or are you talking about an Outboard motor or Out drive?? A properly installed marine engine will have the thrust bearing in the reduction/reverse gear. If it is an OB or Out Drive, the thrust bearing is inside the lower unit. I've never heard of a thrust bearing at the propellor. There should only be a water lubricated cutlass bearing. Please provide more information on what you have, engine/rev. gear, etc. and maybe we can figure a solution. Steve s/v Good Intentions Here is a link that shows a diagram of the boat http://home.worldonline.dk/sejler/scampi/scampi.htm This boat has an hydraulic drive system. The brace that you see in front of the impeller is where the bearing should be ( I think) It looks like a very strong support made out of metal and imbedded in the fiberglass. |
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