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12-24-2008, 03:48 AM
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#1
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Ensign
Join Date: Oct 2008
Posts: 6
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We urgently need some help with our shaft seal, which leaking substantially. We have a maincraft deep sea seal, which has just been serviced while we had our shaft out and a new cutlass bearing fited. We asked for it to be replaced but the engineers said it was still fine. The previous leaking was attributed to a bent shaft.
It has always leaked to a degree, worse with higher engine revs. Now it gushes when underway, even at very low revs. The engineers have all left for the Christmas break and are shut all next week. We have tried adjusting the seal faces etc, but are convinced that it has something to do with the water feed (too much pressure) because it drips constantly when there is no motor running. I've searched online but nothing I've come across has any info on the water feed. Does anyone have the manual for installing a manecraft deep sea seal that they wouldnt mind scanning, or know if this seal for slow speeds (e.g under 1200 rpm) needs to have additional water injection, maybe its been incorrectly fitted all along.
Thanks so much for any help with this
Jacquie
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12-24-2008, 05:19 PM
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#2
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Moderator
Join Date: Jun 2007
Home Port: Washington DC
Vessel Name: SV Mahdee
Posts: 3,236
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Quote:
Originally Posted by jacquiee
We urgently need some help with our shaft seal, which leaking substantially. We have a maincraft deep sea seal, which has just been serviced while we had our shaft out and a new cutlass bearing fited. We asked for it to be replaced but the engineers said it was still fine. The previous leaking was attributed to a bent shaft.
It has always leaked to a degree, worse with higher engine revs. Now it gushes when underway, even at very low revs. The engineers have all left for the Christmas break and are shut all next week. We have tried adjusting the seal faces etc, but are convinced that it has something to do with the water feed (too much pressure) because it drips constantly when there is no motor running. I've searched online but nothing I've come across has any info on the water feed. Does anyone have the manual for installing a manecraft deep sea seal that they wouldnt mind scanning, or know if this seal for slow speeds (e.g under 1200 rpm) needs to have additional water injection, maybe its been incorrectly fitted all along.
Thanks so much for any help with this
Jacquie
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I don't know anything about your particular shaft seal, but googling the issue I see the following info which may be helpful to you:
From this site comes this info:
The maneCraft seal comprises two main components. The stationary seat assembly and the rotating seal assembly, (see Fig 1), both moulded from tough, oil resistant chloroprene. The stationary seat has a solid bronze ring bonded into it and is clamped onto the stern tube with two stainless clips, this part remains stationary. Incorporated into the stationary seat is a red emergency sealing clip. This safety feature is for an emergency only and is protected by a tamper proof tag.
Under no circumstances should the shaft be rotated whilst this clip is tight. The rotating seal assembly is clamped onto the shaft whilst being compressed against the seat. As the shaft rotates, so does the seal assembly. The seal rotates against the stationary bronze seat, lubricated by the water inside the seal, and the water flush/air vent.
Is it possible that you've tightened the clip referenced and rotated the shaft?
Pic below stationary part on left, rotating part on right---
Better pic here or here
Further info found here:
Deep Sea Seals Ltd
4 Marples Way
Havant
PO9 1NX (Road Map)
Hampshire
Tel: 023 9249 2123
Fax: 023 92492470
www.wartsila.com
I hope this is helpful to you.
It seems that if you have NOT activated the emergency clip, you would be able to do so to stop leaking but then would have to replace a part or deal with it before you could use your shaft/engine again.
Finally, if you believe that you will have to replace the seal while you're in the water, there are many issues with doing so in emergency all rather dependent upon your own boat and prop/propshaft configuration. Please do let us know how things are turning out. Where are you located, btw?
Good luck,
Brenda
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12-24-2008, 05:25 PM
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#3
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Moderator
Join Date: Jun 2007
Home Port: Washington DC
Vessel Name: SV Mahdee
Posts: 3,236
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also--
your water flushing probably comes from a feed off your engine raw water line. You may have a valve that lets you adjust the water flow. This flushing, if set up in this manner, would only provide water when the engine is on. You may wish to trace your water flush line, check and see where it comes from and if it is pumped by its own pump vs your engine raw water pump. If there is a valve to adjust flow, you can shut it down to see if this gets rid of your drip. It appears debris could accumulate between the rotating and stationary parts of this set up. That would be expected given the looks of this set up. If so, there should be a means of clearing stuff out of the interface between the dry/wet parts of your system but without a manual, I wouldn't know where you should begin such an endeavor. If debris collects in that location, there could be pressure against the seals and you'd see leaking. That should not incur an emergency unless you're running your engine and cause damage to the seals with the debris.
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12-24-2008, 08:05 PM
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#4
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Ensign
Join Date: Oct 2008
Posts: 6
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Quote:
Originally Posted by redbopeep
also--
your water flushing probably comes from a feed off your engine raw water line. You may have a valve that lets you adjust the water flow. This flushing, if set up in this manner, would only provide water when the engine is on. You may wish to trace your water flush line, check and see where it comes from and if it is pumped by its own pump vs your engine raw water pump. If there is a valve to adjust flow, you can shut it down to see if this gets rid of your drip. It appears debris could accumulate between the rotating and stationary parts of this set up. That would be expected given the looks of this set up. If so, there should be a means of clearing stuff out of the interface between the dry/wet parts of your system but without a manual, I wouldn't know where you should begin such an endeavor. If debris collects in that location, there could be pressure against the seals and you'd see leaking. That should not incur an emergency unless you're running your engine and cause damage to the seals with the debris.
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Hi Redbopeep, we tried turning off the raw water feed which comes off the engine raw water feed, leak has totally stopped. Even when it was only a bit on, it leaked. We'll give it a short run today and see how it goes. I'm a bit worried that the water is meant to be there, for additional cooling, but after a web search, I not so sure for these slower rev units.
Thanks for responding. We are in Brisbane, Australia
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04-27-2009, 02:54 AM
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#5
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Ensign
Join Date: Apr 2009
Posts: 6
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Hello , try this, i have a strong dripless shaft seal, last season i decide to replace the old one for a brand new, i take off the shaft, prop, etc....
we clean the shaft and put everithing together in the boat, the splash day come, the travelift operator suspend the boat in the water wen i check for leaks , nothing wrong, i start the perkins and motor to the mooring, later i recheck bilge for water and foun salt water in the bilge, ouchhhhhh.... the seal is leaking, bad news. this how i fix it:
1 - take a fine piece of sand paper like 400 grade,
2 - start the engine and put the gear in backward ,
3 - take the sand paper and start to clean the area close to the seal until you feel the area smooth, no dings or scrachts,
4 - move the seal to this area and check again for leaks.
i hope work for you, for me no more leaks, not a drop.
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08-08-2009, 01:31 PM
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#6
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Ensign
Join Date: Jun 2008
Posts: 15
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Hi Having had the same issue you will probably find the two faces are not lined up corerectly and at high spead the water come gushing in
Firstly the water must drip once ever few seconds to lubricate the faces of the seal
If you run the motor and engage the shaft with the boat secured at the marina and run the motor at say 1500 RPM adjust the water pressure to say a drip every 2-5 second then reduce the revs to idle and see if the drip is the same,
If it gushes in the seals are no aligned properly turn off the motor
Turn on the bilge pump and pull the frontseal back from the fixed seal water will come in but you must check if the seal is square to the shaft at the Vertical and horizontal planes using engineers square. if its not loosen the back clamp and adjust to suit
once this done push the front seal up to the fixed seal, To ensure the front seal is square to the shaft use a piece of emery cloth with a cut edge and wrap it around the shaft in front of the seal about 6mm from the seal. The cloth is wrapped around itself and basically the end is square on the shaft. the distance between the shaft and the seal should be the same all around if not adjust and retighten up the clamp
There should positive pressure on the seals but not too much, Go back to the start and run the motor again see how you go,
Many people spend a fortune replacing seals and the initial installation or change have not been correctly.
I have never replace this seal however I do carry a spare,
Regards
RossMonty
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08-09-2009, 03:32 AM
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#7
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Admiral
Join Date: Oct 2004
Posts: 3,067
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As Jacquiee never returned after Christmas day 2008 - it is probable that the leak stopped and the boat did not sink.
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