I have just pulled my prop shaft and found the cutlass bearing completey trashed. The folks I have doing the work say that it looks like the bearing was not getting enough water to keep it cooled properly and are recommending plumbing a fitting into the stuffing box to allow water to be pumped into the front end of the bearing. They are further recommending diverting a small amount of water from the raw water cooling loop of the engine to do this. Has anyone else installed this kind of bearing cooling setup? Any thoughts? Thanks, Kevin S/V Weekend Pass Morgan 321
Trashed Cutlass Bearing
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Cutless bearing
There has just been a lengthy discussion of this subject as it relates to Beneteaus on the Beneteau Google list. Here is the most recent discussion: Dlm48@aol.com to Beneteau-Owners More options 6:43 am (4 hours ago) In a message dated 26/01/2006 04:34:06 GMT Standard Time, mohawk@msn.com writes: It is necessary, you are lubricating your shaft by forcing the water from behind the bearing by forcing it through as your shaft turns . The cool water is pushed through in another word all the time. Bearing being in the water as the shaft turns does not allow enough water to climb up through the bearing and since the other end is in your boat and stopped either by stuffing box or drip less the water starts boiling and evaporate due to the friction thus your bearing is not getting cool. Marratu Oceanis 461 #168 Galveston, Texas M. M. Bayegan ----- Original Message ----- From: Robert Gales To: Beneteau-Owners@googlegroups.com Sent: Wednesday, January 25, 2006 8:08 PM Subject: {Beneteau Owners} Cutlass bearing hose Is this hose to supply water to the cutlass bearing necessary? Volvo says that the bearing needs to be under water so it can be lubricated. So is the hose really needed? The installer of my new Volvo D130 said it may not be necessary (as did some sailnet list members) due to the fact it is not a high rpm turning shaft. My new engine is being installed this week and I want to make sure everything is hooked up correctly. I am still concerned about the stiffness of the Volvo seal. Thanks for any comments, Bob Gales Welches, OR By cutlass bearing it take it that we are meaning shaft log/stuffing box - the cutlass bearing should be happily immersed in the water at all times even on the Oceanis range where it is in a skeg in the hull. On a sail boat a water injected shaft log is a nice to have feature but is not needed. It is needed on a planing powerboat when there is liable to be enough movement through the water to drain the prop tube the combination of that and the fact that the boat will plane on top of the water not deeply immersed in it - these factors would cause the high sped aft flowing water flow to drain the water out of the prop tube and therefore the bearing would run dry - so to avoid that you force water in there constantly. Without this feature on your sailboat you have to bleed the tube so that there is water in there - you do that at launching by burping the seal seat until you get water out. In order to avoid the need for this 'bleeding at launch time' some boat manufacturers use the water injection nipple and attach a vent line to it that runs above the water line and can either have a loop or a valve in it. Cant imagine the water boiling or evaporating in the shaft of any Bennie sailboat. The shaft is not turning fast enough to create enough heat for even localised boiling and we sail in millions/trillions of gallons of water so any evaporation IF it did or could take place would be instantly be replaced. So a water injected shaft log is a nice to have thing - but not really required on any sailboat and would seem to cause more problems than it solves so in reality is not nice to have feature. don't worry if you have one and don't worry if you don't. i am not sure what the 'official' rules in any marine certification regime are but i think it is 15 knots and above before you need a water injected shaft log. regards David
There has just been a lengthy discussion of this subject as it relates to Beneteaus on the Beneteau Google list. Here is the most recent discussion: Dlm48@aol.com to Beneteau-Owners More options 6:43 am (4 hours ago) In a message dated 26/01/2006 04:34:06 GMT Standard Time, mohawk@msn.com writes: It is necessary, you are lubricating your shaft by forcing the water from behind the bearing by forcing it through as your shaft turns . The cool water is pushed through in another word all the time. Bearing being in the water as the shaft turns does not allow enough water to climb up through the bearing and since the other end is in your boat and stopped either by stuffing box or drip less the water starts boiling and evaporate due to the friction thus your bearing is not getting cool. Marratu Oceanis 461 #168 Galveston, Texas M. M. Bayegan ----- Original Message ----- From: Robert Gales To: Beneteau-Owners@googlegroups.com Sent: Wednesday, January 25, 2006 8:08 PM Subject: {Beneteau Owners} Cutlass bearing hose Is this hose to supply water to the cutlass bearing necessary? Volvo says that the bearing needs to be under water so it can be lubricated. So is the hose really needed? The installer of my new Volvo D130 said it may not be necessary (as did some sailnet list members) due to the fact it is not a high rpm turning shaft. My new engine is being installed this week and I want to make sure everything is hooked up correctly. I am still concerned about the stiffness of the Volvo seal. Thanks for any comments, Bob Gales Welches, OR By cutlass bearing it take it that we are meaning shaft log/stuffing box - the cutlass bearing should be happily immersed in the water at all times even on the Oceanis range where it is in a skeg in the hull. On a sail boat a water injected shaft log is a nice to have feature but is not needed. It is needed on a planing powerboat when there is liable to be enough movement through the water to drain the prop tube the combination of that and the fact that the boat will plane on top of the water not deeply immersed in it - these factors would cause the high sped aft flowing water flow to drain the water out of the prop tube and therefore the bearing would run dry - so to avoid that you force water in there constantly. Without this feature on your sailboat you have to bleed the tube so that there is water in there - you do that at launching by burping the seal seat until you get water out. In order to avoid the need for this 'bleeding at launch time' some boat manufacturers use the water injection nipple and attach a vent line to it that runs above the water line and can either have a loop or a valve in it. Cant imagine the water boiling or evaporating in the shaft of any Bennie sailboat. The shaft is not turning fast enough to create enough heat for even localised boiling and we sail in millions/trillions of gallons of water so any evaporation IF it did or could take place would be instantly be replaced. So a water injected shaft log is a nice to have thing - but not really required on any sailboat and would seem to cause more problems than it solves so in reality is not nice to have feature. don't worry if you have one and don't worry if you don't. i am not sure what the 'official' rules in any marine certification regime are but i think it is 15 knots and above before you need a water injected shaft log. regards David
Not a cutlass Bearing
Unless I've been reading this post wrong. Just want to be clear. The cutlass bearing is typically located on the strut, right before the shaft reaches the propeller. not up into the shaft log & stuffing box. If the guys in the yard have been using that terminology for your stern tube/shaft log, I'd find someone else to look at it...If you have a dripless (PSS) type shaft seal, there should be a bellows that you can burp to ensure there is water & not air to lube the shaft. If you have a packing gland (stuffing box) with flax rope or teflon packing material, you probably have it screwed down too tight to let any water past to lube, simply loosen it up a bit (check the archives for how to do this). RPM's are too slow to need any elaborate lube system. Good luck!
Unless I've been reading this post wrong. Just want to be clear. The cutlass bearing is typically located on the strut, right before the shaft reaches the propeller. not up into the shaft log & stuffing box. If the guys in the yard have been using that terminology for your stern tube/shaft log, I'd find someone else to look at it...If you have a dripless (PSS) type shaft seal, there should be a bellows that you can burp to ensure there is water & not air to lube the shaft. If you have a packing gland (stuffing box) with flax rope or teflon packing material, you probably have it screwed down too tight to let any water past to lube, simply loosen it up a bit (check the archives for how to do this). RPM's are too slow to need any elaborate lube system. Good luck!
Clarification
The failed part was the cutlass bearing. The idea is that water injected through a fitting on the stuffing box will move down the log and out through the bearing to keep it cool. Kevin
The failed part was the cutlass bearing. The idea is that water injected through a fitting on the stuffing box will move down the log and out through the bearing to keep it cool. Kevin
I assume
by the way it is described, you do not have a strut and your cutless bearing is inside of your stern tube. That was the set-up on my Cal 34 III. However, I don't understand why you would have to inject water down through the stern tube and cutless. I guess there is no dripping what so ever from your stuffing box. As long as there is dripping, there is enough water flow to lub the cutless bearing. You may have the stuffing box too tight as was previously mentioned. Greg
by the way it is described, you do not have a strut and your cutless bearing is inside of your stern tube. That was the set-up on my Cal 34 III. However, I don't understand why you would have to inject water down through the stern tube and cutless. I guess there is no dripping what so ever from your stuffing box. As long as there is dripping, there is enough water flow to lub the cutless bearing. You may have the stuffing box too tight as was previously mentioned. Greg
Just so we are all on the same page, got a pic?
To make sure it is the cutless bearing vs. stuffing box.
To make sure it is the cutless bearing vs. stuffing box.
cutlass bearing life
Franklin,It is my understanding that a cutlass bearing should last for 1000 hours of use.This assumes that the shaft is aligned correctly etc etc
Franklin,It is my understanding that a cutlass bearing should last for 1000 hours of use.This assumes that the shaft is aligned correctly etc etc
Franklin --- If properly set up
meaning - high polished and perfectly concentric shafting, precise fit/clearances, the amount of 'press fit' into the housing, etc. then a cutless should last for many YEARS. What wears out a cutless is the amount of undisolved abrasive particulate in your local water, shaft misalignment, too loose or too tight a bearing, 'shaft whip', etc.
meaning - high polished and perfectly concentric shafting, precise fit/clearances, the amount of 'press fit' into the housing, etc. then a cutless should last for many YEARS. What wears out a cutless is the amount of undisolved abrasive particulate in your local water, shaft misalignment, too loose or too tight a bearing, 'shaft whip', etc.
Thanks all
I feel a little better now. I'm not planning on hauling my boat out this year and that's the one thing I can't check. What has me a little worried about it is that last winter when I bought the boat, the engine, if I'm not mistaken, seems to vibrate more now at idle then when I first bought the boat, especially when it's cold. I now do what the manual says and starting it with a little throttle in neutral and that has reduced the vibration. I did align the shaft because I definately had vibration at higher speeds when I bought it and I don't seem to have that now. I may need to replace my motor mounts
I definately don't want to screw up my tranny because the bearing is bad. Is it possible to tell if the bearing is bad without hauling it out?
I feel a little better now. I'm not planning on hauling my boat out this year and that's the one thing I can't check. What has me a little worried about it is that last winter when I bought the boat, the engine, if I'm not mistaken, seems to vibrate more now at idle then when I first bought the boat, especially when it's cold. I now do what the manual says and starting it with a little throttle in neutral and that has reduced the vibration. I did align the shaft because I definately had vibration at higher speeds when I bought it and I don't seem to have that now. I may need to replace my motor mounts
I definately don't want to screw up my tranny because the bearing is bad. Is it possible to tell if the bearing is bad without hauling it out?
You should really check with the boat out of the
water. I use a machinists dial indicator and usually 'start to think' about replacing when the 'slop' gets to be around 0,015" for a 1.5"dia shaft - but that check comes only after I properly re-align the engine etc.
water. I use a machinists dial indicator and usually 'start to think' about replacing when the 'slop' gets to be around 0,015" for a 1.5"dia shaft - but that check comes only after I properly re-align the engine etc.
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