Dripless Repair question. Haulout?

[Streff]

I have PYS dripless on the shafts. A small white plastic coupling interfaces between the hose carrying sea water and the rubber body of the dripless. I noticed on our last trip out that this plastic interface could benefit from servicing.

I was planning to install a new coupling. It seems to be a straightforward job. I was watching a youtube video on another topic and they mentioned that the boat needs to be out of the water to replace this small component. I was surprised to hear that.

I was planning on closing the seacock that feeds the dripless tube and also possibly cramping the hose before tackling the project. So I am not sure why a haul-out is required?.

I am hoping to learn your opinion on the need to be on the hard.

Thank you much

Streff

 

[rgano]

That sounds like the PYI lawyers talking with the idea that somebody out there is stupid enough as to be incapable of stemming the small in rush of water through the small dripless packing cooling hose connection and thus allowing their boat to sink under them. Think the story of the little Dutch boy with his finger in the dike. Not a big deal.

 

[Portage_Bay]

Possibly the Youtube reference to haulout required is when replacing the dripless seal entirely.

To do that the shaft coupling flange at the transmission must be disconnected then removed. Then the shaft is slid back far enough to swap out all the parts. The sea is free to flow in while this is done.

 

[rochepoint]

If you are talking about the hose barb fitting that screws into the carbon stator for the raw water injection hose. If yours is white plastic or nylon (our is nylon) do not replace it with a metal one as used in the new seals as the new ones have a nylon insert that the hose barb screws into, with the old style stator only use a nylon fitting. This is directly from PYI.

 

[Streff]

Thank you all for the great comments. Now that I know I can do the replacement safely, I am saving the part onboard but not servicing it right away.

On another note when I noticed the nylon connection looking displaced. I found something interesting after the bottom was painted last month. A line of black paint appeared on either side of the shafts. About 20” on either side of each shaft in a perpendicular way. I cleaned the area and did not see it reappear.

Thanks again for the help.

Streff

 

[RickyD]

If I may Hi-Jack this as it is a similar situation. My stbd dripless was dripping. On further analysis it looks like the housing that the shaft goes through is no longer completely sealed and is oozing water at a very slow rate. Signs of corrosion on the bolts is becoming pronounced when compared to the port side. Also, watching it at 10 knots there is a very very small wobble not seen on the port side. All systems are cool to the touch. A little warmer than the shaft but with only a couple degrees warmer. I'm preparing for a scheduled haul out anyway. Cutlass bearings will be checked. That sealed area must be resealed. What comments might you have on this? I have no experience in this area.

 

[Duetto]

you don't mention what type dripless seal you have. can you take a pic?

 

[RickyD]

I'm not sure what make it is. I'll will take pictures later this week. I really don't know how these systems are placed in the boat preventing water incursion. I'm hoping not to have to pull the shaft.

 

[sbman]

I'm not sure what make it is. I'll will take pictures later this week. I really don't know how these systems are placed in the boat preventing water incursion. I'm hoping not to have to pull the shaft.

Whatever system it is, you would not normally need to pull the shaft out of the boat, but you will most likely have to disconnect it from the transmission and remove the flange/shaft adapter. At that point you are 90% of the way to removing the shaft, and if your rudder isn't in the way it is not a big deal to remove it at that point.

 

[Duetto]

they work by providing a) a seal (mechanical or lip) to the shaft b) a hose or bellows which holds that seal c) a hose clamp which attaches the hose/bellows to the stern tube. taken together this allows the prop shaft to exit the boat thru the stern tube without letting water in.

if the rubber hose/bellows is leaking from a tear/hole in the rubber you need to have it checked right away.checked

 

[RickyD]

they work by providing a) a seal (mechanical or lip) to the shaft b) a hose or bellows which holds that seal c) a hose clamp which attaches the hose/bellows to the stern tube. taken together this allows the prop shaft to exit the boat thru the stern tube without letting water in.

if the rubber hose/bellows is leaking from a tear/hole in the rubber you need to have it checked right away.checked

The leak does not seem to be coming from the bellows. It seems to be further back. There are no drips from the bottom of the bellows but it could be coming from under the bellows, under the clamps, and out at the after end. It is hard to determine. I will check it out better later today with mirrors and lights. I checked out the installation videos on line so now I understand what is going on better. I may have a problem with the seal around the shaft tube as it exits the boat.

 

[Duetto]

that would be a crack in the stern tube or where the stern tube is glassed into the hull. i think that's rare short of some kind of a collision. focus on the dripless seal and bellows and figure out what kind of dripless seal you have.

good luck

 

[firehoser75]

RickyD,
If your shaft seal looks like the ones on this site PYI Inc. | PSS Shaft Seal, it is a PSS seal. The bellows is a maintenance item and should be replaced every 6 years if the regular seal, or every 10 years if it is the new improved version. This is manufacturer's recommendations. I am no expert on insurance (and the application of that type of law), but I would suggest that an insurer may not cover water damage caused by a failed, outdated seal???? Not something I would chance.
To replace this seal, the boat must be hauled, and the shaft disconnected and slid back allowing for removal and reinstallation. To my thinking, why not remove the shaft and change out the cutlass bearing as well, especially if it is the 10 year mark, as you would be almost there labour wise anyway?
These bellows provide the compression (springiness) to "make the seal", and over time lose this springiness as well as the fact that the rubber can deteriorate, especially if exposed to oils and fuels. If your leak is not the seal itself, then additional repairs to the stern tube will be required and removal of the seal would probably be necessary anyway for that.
Good luck

 

[Frank60]

On another note when I noticed the nylon connection looking displaced. I found something interesting after the bottom was painted last month. A line of black paint appeared on either side of the shafts. About 20” on either side of each shaft in a perpendicular way. I cleaned the area and did not see it reappear.

Thanks again for the help.

Streff

The line of 'black paint' was probably carbon spray. If the seal is not sealing completely, you can get a fine water spray that will take some carbon with it and make an ugly black line. See picture. I had that problem and had to replace the seals to get rid of it as they couldn't be compressed any further. I actually upgraded the seals to the Pro shaft seal as I had too many problems trying to get the regular PSS to work. Haven't had a problem since.

Glad yours went away on its own. Maybe it was just some initial misalignment of the faces on the seal after the haulout although I've never heard of that.

 

[Trimjb]

The leak does not seem to be coming from the bellows. It seems to be further back. There are no drips from the bottom of the bellows but it could be coming from under the bellows, under the clamps, and out at the after end. It is hard to determine. I will check it out better later today with mirrors and lights. I checked out the installation videos on line so now I understand what is going on better. I may have a problem with the seal around the shaft tube as it exits the boat.

Did you check the hose clamp for tightness around the stern tube?
Just a thought.

 

[CmdrDick]

Pre-loaded carbon Shaft seals and their cooling sources ??

I was surprised to read the part about his closing a thru hull to stop water flow thru the small rubber shaft seal cooling water line.
In my boat, with SBC Crusaders, the cooling water source is from the bottom of the exhaust manifold riser. This water comes from the sea water cooling pump, and is under pressure.
I've never had a problem with these seals and I occasionally push the rubber boot back just far enough by hand with the shaft spinning to let a flood of water out and then inspect it for proper sealing of the SS ring to the carbon surface.
That is the only way that I am assured of water flow in what seems to be a totally sealed joint. I never see even a drop of water in the bilge there.
My thinking was that the graphite to SS seal was water tight.
Am I supposed to see a drop or two leaking like we had with mechanical packing in the old days?

 

[FF]

If the boat was built with a conventional stuffing box and converted to the dripless , you can probably do away with the dripless and simply use modern packing in the older system.

No danger of a rubber bellows rupturing and causing a leak few bilge pump systems can handle no maint. after installation, can be renewed in the water , no haul out required.

 

[Puffin_NT32]

Comment to ROCHEPOINT... I have a PSS seal on my NT32. I replaced the nylon hose barb last year concerned about it cracking when I occasionally disconnect the hose during raw water pump impeller replacement. I replaced it with a brass hose barb, and I have a brass plug to cap the hole during raw water pump maintenance. When I replace the pump impeller, a little bit of water syphons back through the fuel cooler into the pump. I'm not sure what the issue is with replacing the nylon barb with a brass or stainless barb.

Not to jinx myself, I should point out that after 2,400 hours and 15 years, my original PSS seal is still doing it's job. No leaks, firm bellows pressure (never adjusted), with external bellows getting an occasional wipe of 3M 303 Protectant. PSS suggest replacement with their maintenance kit every 6 years (I have the kit). Over the years, I asked PSS reps at boat shows, and my boatyard manager, about installing the maintenance kit, and the response is usually... no leaks, bellows firm and in good shape, don't bother (if it ain't broke, don't fix it). I do check the seal regularly.

 

[CmdrDick]

(if it ain't broke, don't fix it).
After 40 years of flying the big jets, my favorite response to junior officers was (if it ain't broke, don't fix it). If you are not on fire or sinking, Every problem can wait until you are stationary.
Tinkeritis has caused thousands of serious problems over the years when people who were not 100% familiar with the equipment, decided to "Let's try this".

 

[sbman]

Comment to ROCHEPOINT... I have a PSS seal on my NT32. I replaced the nylon hose barb last year concerned about it cracking when I occasionally disconnect the hose during raw water pump impeller replacement. I replaced it with a brass hose barb, and I have a brass plug to cap the hole during raw water pump maintenance. When I replace the pump impeller, a little bit of water syphons back through the fuel cooler into the pump. I'm not sure what the issue is with replacing the nylon barb with a brass or stainless barb.

Not to jinx myself, I should point out that after 2,400 hours and 15 years, my original PSS seal is still doing it's job. No leaks, firm bellows pressure (never adjusted), with external bellows getting an occasional wipe of 3M 303 Protectant. PSS suggest replacement with their maintenance kit every 6 years (I have the kit). Over the years, I asked PSS reps at boat shows, and my boatyard manager, about installing the maintenance kit, and the response is usually... no leaks, bellows firm and in good shape, don't bother (if it ain't broke, don't fix it). I do check the seal regularly.

I do hope you mean bronze. Brass should never, ever be used below the water line or in contact with seawater.