Shaft seal question: 2017 RT25SC/VolvoPenta D3-150

wa7pug

Well-known member
Joined
Apr 25, 2023
Messages
131
Fluid Motion Model
C-26
Vessel Name
Pau Hana Too (or PHT for short)
When we got the survey and bought the boat, one of the survey comments was that shaft seal was too tight and recommended loosening it …
1) Volvo Penta did not use a dripless shaft seal in 2017? Dripless seal technology has been around for a while ... Do you have any idea what shaft seal (Mfg/model – any data?) was used?
2) IF it is supposed to drip, is there any idea what the optimum drip rate should be? I like a dry bilge but also do not want to have the seal go out half way to SJI.

"The more I know, the less I understand ..."
 
Fire the surveyor !!! It is not a good practice to loosen packing. When a gland is over tightened it gets hot and the packing is set at that point. Why would he ever say it was too tight? How does he/she know? Was it running at a high temp? Or is it because it was not leaking? The packing glandes used on Rangers Tugs are designed for log style installations. The water from cooling comes from the engine not the log. This is so the log has water flow to cool the cutlass bearing. The packing gland will not and should not leak if the boat is sitting idle. The gland should only drip when in gear engine running and should be no more than 3 drips per minute. I would not advise loosening the packing. You will have a leak in no time! A properly adjusted packing gland used in a Ranger or Cutwater will be close to a dry bilge. At most there will be a slight mist that comes off when running. I installed a small shield to keep the mist from damaging the engine finish and connectors.

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Properly adjusted packing and no drips when the engine is not in gear.
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wa7pug":16c6k84x said:
When we got the survey and bought the boat, one of the survey comments was that shaft seal was too tight and recommended loosening it …
1) Volvo Penta did not use a dripless shaft seal in 2017? Dripless seal technology has been around for a while ... Do you have any idea what shaft seal (Mfg/model – any data?) was used?
2) IF it is supposed to drip, is there any idea what the optimum drip rate should be? I like a dry bilge but also do not want to have the seal go out half way to SJI.

"The more I know, the less I understand ..."
Picture
The Packing Gland
The packing gland is the watertight connection between the turning propeller shaft and the hull of the boat. This connection gets hot from friction and therefore must be cooled with water. Typically there are products to accomplish the cooling. One, is a dripless seal where water comes in and flows out in a closed system. The second one, is the decades old traditional one of a packing gland. This type is on our Ranger Tug. This photo shows the two parts of the packing gland: the larger compression nut and the thinner locking nut with the the exposed threads. The gland is manually tightened to so no or very, very little water drips when the prop shaft is still and drips about 4 to 8 drips per minute when the shaft is turning. A wet bilge is normal and expected in this system. I have had both systems. The dripless system is nearly maintenance free as long as water is circulating through the system. Clogs can happen in the raw water system and the failure is quick and the fix is expensive.

The traditional packing gland takes no minimal maintenance. Simply ensure the right number of drips is happening and adjust according. When the adjusting nut cannot be tightened any further, the wax impregnated stuffing is replaced. Adjusting the packing gland and replacing the stuffing can be down by the owner. The tools needed to adjust the packing gland are two large adjusting wrenches. These are found in the plumbing department at hardware stores. Steps to adjust the packing gland:
Loosen the thin locking nut by turning toward the port side of the boat. Use a pipe over the handle of the wrench if it will not move. If that does not work, soak the threads with Liquid Wrench or any penetrating oil for several hours or even a day.
Tighten the large compression nut by hand and then a very short turn with a wrench. I have found turning the length of one notch or shoulder on the nut is more than adequate.
Tighten the locking nut.
Picture


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misinger":2rl3pggc said:
wa7pug":2rl3pggc said:
When we got the survey and bought the boat, one of the survey comments was that shaft seal was too tight and recommended loosening it …
1) Volvo Penta did not use a dripless shaft seal in 2017? Dripless seal technology has been around for a while ... Do you have any idea what shaft seal (Mfg/model – any data?) was used?
2) IF it is supposed to drip, is there any idea what the optimum drip rate should be? I like a dry bilge but also do not want to have the seal go out half way to SJI.

"The more I know, the less I understand ..."
Picture
The Packing Gland
The packing gland is the watertight connection between the turning propeller shaft and the hull of the boat. This connection gets hot from friction and therefore must be cooled with water. Typically there are products to accomplish the cooling. One, is a dripless seal where water comes in and flows out in a closed system. The second one, is the decades old traditional one of a packing gland. This type is on our Ranger Tug. This photo shows the two parts of the packing gland: the larger compression nut and the thinner locking nut with the the exposed threads. The gland is manually tightened to so no or very, very little water drips when the prop shaft is still and drips about 4 to 8 drips per minute when the shaft is turning. A wet bilge is normal and expected in this system. I have had both systems. The dripless system is nearly maintenance free as long as water is circulating through the system. Clogs can happen in the raw water system and the failure is quick and the fix is expensive.

The traditional packing gland takes no minimal maintenance. Simply ensure the right number of drips is happening and adjust according. When the adjusting nut cannot be tightened any further, the wax impregnated stuffing is replaced. Adjusting the packing gland and replacing the stuffing can be down by the owner. The tools needed to adjust the packing gland are two large adjusting wrenches. These are found in the plumbing department at hardware stores. Steps to adjust the packing gland:
Loosen the thin locking nut by turning toward the port side of the boat. Use a pipe over the handle of the wrench if it will not move. If that does not work, soak the threads with Liquid Wrench or any penetrating oil for several hours or even a day.
Tighten the large compression nut by hand and then a very short turn with a wrench. I have found turning the length of one notch or shoulder on the nut is more than adequate.
Tighten the locking nut.
Picture


Sent from my iPhone using Tapatalk
https://www.captainjohngray.com/maintenance-and-repairs.html


Sent from my iPhone using Tapatalk
 
So we have opinions of 0-3 drops ... one of the things that occurs to me is that most of us with the tugs do not go very fast - packing should not get overly hot, so maybe there is 'forgiveness' there ... BUT one thing that jumped out of me from one of the above comments, my survey, and my last yard service: above noted to make a plastic shield to prevent slinging spray all over engine compartment, and that is no joke ... wish Ranger did this when they build these things .... but i got reminded of it this week plus above comment. Guess what I am doing Sunday? Fabricating a plastic splash shield - THANK YOU FOR THE REMINDER!!!!
 
So we have opinions of 0-3 drops ... one of the things that occurs to me is that most of us with the tugs do not go very fast - packing should not get overly hot, so maybe there is 'forgiveness' there ... BUT one thing that jumped out of me from one of the above comments, my survey, and my last yard service: above noted to make a plastic shield to prevent slinging spray all over engine compartment, and that is no joke ... wish Ranger did this when they build these things .... but i got reminded of it this week plus above comment. Guess what I am doing Sunday? Fabricating a plastic splash shield - THANK YOU FOR THE REMINDER!!!!
Photos of the completed splash guard please
 
Photos of the completed splash guard please
Brian - I had the sheet plastic one in last week and it is ok but then the one with the milk carton makes more sense as far as small enough but big enough. My R25 is trailerable so I am going to bring it home to my home shop in Oct/Nov and get some acrylic and make a "better milk jug" only because I can ... bottom line - clean engine compartment protects all of the components in there. I think you saw my link with the photos (only a couple) and that thread had one of the guys milk jug solution. If you need more info just email me pauhanatoo@gmail.com and I will include photos of what I did .... I think best route to go is do what makes sense to get you thru the season and then do something profound over winter. Ping me if you want to discuss, I am in Central Park WA so easy to find. Doug
 
Here is the link to a google album: https://photos.app.goo.gl/4YvmaR3EaCAcWR1E6
The first one is the milk jug idea that was posted on the forum - you can see why I like it - and the other two show the one I made that is bigger ... I was solving the wrong problem so I will just take the acrylic and make a nicer one that fits tidy like the milk jug only clear... Hope this helps ....
 
The milk jug.
 
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