My C350 came with a dripless shaft seal. I believe the brand is PSS. It is the type that has a stainess steel collar attached to the prop shaft and a rubber bellows attached to the hull that has a metal fitting which rubs on the stainless collar. On the older models of this seal it was nessacary to "burb" the seal when you first put it in the water. The later versions came with a hose that provides water to this seal to keep it from running dry and burning up. I noticed this spring during a close inspection after a couple of months of no use that the two metal parts were somehow bonded tight together. I tried to burp the fitting to check for the water to flow out but did not have the strenght to pull the seal back. I tried to turn the prop shaft and the rubber bellows twisted along with the little movement that I was able to achieve. I finally broke it free by levering the plumbing fitting at the top where the hose enters. Once I had broken it free I was able to turn the shaft by hand but it felt rough. When I got back from a short boat ride the shaft felt normal again. There was also a small vibration that went away after a few minutes of running I assume it was corrosion that bonded the two metal parts together. I can only wonder what would have happened if I had put it in gear without checking. A failure of that rubber bellows due to overheating or tearing could ruin your whole day. Any suggestions regarding how to handle that sort of emergency?. That would be a hard leak to stop.
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This is going to sound like I am coming
in from left field but i have read about an archaic make shift method called a "sore leg". Stay with me here cause this gets kinda crazy. You sew a piece of a pants leg around the shaft and lash one end th=o the stern tube very securely pour into the open end about one cup of tallow and lash the cloth to the shaft without getting it too tight work the tallow into the cloth and the lashings on the shaft. run the engine slowly. I have only seen one reference to this and have tried to find others with no success.
in from left field but i have read about an archaic make shift method called a "sore leg". Stay with me here cause this gets kinda crazy. You sew a piece of a pants leg around the shaft and lash one end th=o the stern tube very securely pour into the open end about one cup of tallow and lash the cloth to the shaft without getting it too tight work the tallow into the cloth and the lashings on the shaft. run the engine slowly. I have only seen one reference to this and have tried to find others with no success.
Might work
Ross, any port in a storm. That might work, if the boat didn't sink before you got the deal put together. Seriously though, I have wondered about this. With a regular packing gland, you can makeshift something, to slow it down enough to get somewhere to fix it right. I have been told that an old pair of panty hose will work fairly well. Assuming you have a good bilge pump. In the rare event of a dripless failure, then what. I don't know about the rest of you on here, but Murphy's law seems to be constantly nipping at my heels. Would love to hear any other ideas on this.
Ross, any port in a storm. That might work, if the boat didn't sink before you got the deal put together. Seriously though, I have wondered about this. With a regular packing gland, you can makeshift something, to slow it down enough to get somewhere to fix it right. I have been told that an old pair of panty hose will work fairly well. Assuming you have a good bilge pump. In the rare event of a dripless failure, then what. I don't know about the rest of you on here, but Murphy's law seems to be constantly nipping at my heels. Would love to hear any other ideas on this.
The PSS..
Should not have any metal to metal! There should be a stainless steel rotor that rotates against a carbon rotor. If you have metal to metal faces you have something other than a PSS. I can't imagine what could have precipitated the two seal faces sticking together? This should not happen.. Here's a link to what a PSS should look like. The picture was taken during the installation so the stainless rotor is separated from the carbon rotor. The carbon rotor has the plastic barbed fitting in it. http://www.pbase.com/mainecruising/image/72621935
Should not have any metal to metal! There should be a stainless steel rotor that rotates against a carbon rotor. If you have metal to metal faces you have something other than a PSS. I can't imagine what could have precipitated the two seal faces sticking together? This should not happen.. Here's a link to what a PSS should look like. The picture was taken during the installation so the stainless rotor is separated from the carbon rotor. The carbon rotor has the plastic barbed fitting in it. http://www.pbase.com/mainecruising/image/72621935
A little off the subject
Mainesail, looks all new and shiny down in there. Do you not safety wire the coupler set screws. I didn't used to, but last summer I anchored up, stuck it in reverse to set the anchor, and the prop. dinged the rudder on the it's way to backing out. Didn't do any real damage and I managed a jury rig to get home, but my set screws are now safety wired.
Mainesail, looks all new and shiny down in there. Do you not safety wire the coupler set screws. I didn't used to, but last summer I anchored up, stuck it in reverse to set the anchor, and the prop. dinged the rudder on the it's way to backing out. Didn't do any real damage and I managed a jury rig to get home, but my set screws are now safety wired.
Nice & Easy..
I stated the photo was taken during installation. If you click the picture it should reduce size and you can see the rest of my article where there are pics of the nuts wired together or click here: http://www.pbase.com/mainecruising/pss_shaft_seal
I stated the photo was taken during installation. If you click the picture it should reduce size and you can see the rest of my article where there are pics of the nuts wired together or click here: http://www.pbase.com/mainecruising/pss_shaft_seal
If it's sea crud
If it's sea crud and salt in between the carbon and stainless it should not rip the Kevlar reinforced bellows unless it's at the end of its useful life anyway. Both systems, the conventional stuffing box and the PSS, are both connected to the hull via a piece of rubber. Both systems require periodic replacement of the rubber! I fail to see how a belows reinforced with Kevlar, the stuff they make bullet proof vests out of, is more dangerous than a rubber hose reinforced with nylon string? I have personally replaced three hoses on standard stuffing boxes in my life time, one cracked and leaking, and none yet on a PSS. I have also had three shafts ruined by traditional stuffing boxes prior to products like Gore GFO and none by a PSS. I have also never had the two surfaces stick together and I've now owned four boats with PSS shaft seals so my guess is that this is a very rare instance. Call PSS and describe your problem they have very good tech support!
If it's sea crud and salt in between the carbon and stainless it should not rip the Kevlar reinforced bellows unless it's at the end of its useful life anyway. Both systems, the conventional stuffing box and the PSS, are both connected to the hull via a piece of rubber. Both systems require periodic replacement of the rubber! I fail to see how a belows reinforced with Kevlar, the stuff they make bullet proof vests out of, is more dangerous than a rubber hose reinforced with nylon string? I have personally replaced three hoses on standard stuffing boxes in my life time, one cracked and leaking, and none yet on a PSS. I have also had three shafts ruined by traditional stuffing boxes prior to products like Gore GFO and none by a PSS. I have also never had the two surfaces stick together and I've now owned four boats with PSS shaft seals so my guess is that this is a very rare instance. Call PSS and describe your problem they have very good tech support!
Thanks Mainsail
That's the same model alright. It was my mistake about metal to metal. I also believe that it is no mystery that it must have been basic "sea crud" that is responsible for the sticking exacerbated by a couple of months (or was it 3) of non-use. My main reason for the post was to solicit emergency procedures for a failure. I found the things you said about the inner construction to be reassuring. I always try to imagine the proper response for any possible emergency and this one kind of baffles me. Perhaps extra bilge pump capacity is the answer just in case the thing ever does fail. It can be hard to come up with ideas once the excrement hits the ventilator.
That's the same model alright. It was my mistake about metal to metal. I also believe that it is no mystery that it must have been basic "sea crud" that is responsible for the sticking exacerbated by a couple of months (or was it 3) of non-use. My main reason for the post was to solicit emergency procedures for a failure. I found the things you said about the inner construction to be reassuring. I always try to imagine the proper response for any possible emergency and this one kind of baffles me. Perhaps extra bilge pump capacity is the answer just in case the thing ever does fail. It can be hard to come up with ideas once the excrement hits the ventilator.
PSS Dripless Seal
I have had great results with my dripless seal. If you run a clear plastic hose from the barb you can see at a glance if there is water in the unit. I have heard of some early units backing off and folks used to put a zinc in front of the metal part as a backup in case the set screws in the collar came loose. Now PSS uses double set screws--one on top of the other-- and I understand the collar will not shift. I have to believe that the bellows was dry in this case. Even after three months of no use what sea crud is going to get past the shaft and grow in the anerobic environment inside the bellows?
I have had great results with my dripless seal. If you run a clear plastic hose from the barb you can see at a glance if there is water in the unit. I have heard of some early units backing off and folks used to put a zinc in front of the metal part as a backup in case the set screws in the collar came loose. Now PSS uses double set screws--one on top of the other-- and I understand the collar will not shift. I have to believe that the bellows was dry in this case. Even after three months of no use what sea crud is going to get past the shaft and grow in the anerobic environment inside the bellows?
Good idea on the clear hose, Tom
I might try that. I know the shaft seal was not dry though because the last time the boat was out of the water was in December when the bottom was painted. I burbed the shaft seal right after the boat was put back in the water. Everything seemed normal at that time. Considering what Mainsail said about how tough the bellows is, there may not be any problem at all. Perhaps the gunk is not that unusual in a situation where the boat sits idle (in salt water) for a few months. Consider that most people would not try to turn the prop shaft by hand before starting the engine and in all probability the roughness I felt would self-clean on the first couple of minutes of rotation. Thanks for the help everyone. I am still curious to know a good technique for stopping a leak if that part ever does self-destruct.
I might try that. I know the shaft seal was not dry though because the last time the boat was out of the water was in December when the bottom was painted. I burbed the shaft seal right after the boat was put back in the water. Everything seemed normal at that time. Considering what Mainsail said about how tough the bellows is, there may not be any problem at all. Perhaps the gunk is not that unusual in a situation where the boat sits idle (in salt water) for a few months. Consider that most people would not try to turn the prop shaft by hand before starting the engine and in all probability the roughness I felt would self-clean on the first couple of minutes of rotation. Thanks for the help everyone. I am still curious to know a good technique for stopping a leak if that part ever does self-destruct.
How would you fix it..
How would you fix it if the rubber hose on a regular stuffing box let go? I guess you'd fix the PSS the same way. One way would be to re-clamp it, if the bellows tore, by sliding the bellows back beyond the tear and re-clamping to the shaft log. You'd also need to slide the stainless rotor back to meet the bellows. These bellows are quite long when not compressed and may give you enough room to do this. On the other hand the rubber hose on a traditional stuffing box is quite short and filled with the male end of the stuffing box which would not allow you to move it much. Another way would be to wrap it in saran wrap about ten times then go over that with electrical tape or self adhering rigging tape then duct tape over that. Any of these methods should get you into port but I would not worry about it. Insurance claims show that far more boats sink due to traditional stuffing boxes than PSS types..
How would you fix it if the rubber hose on a regular stuffing box let go? I guess you'd fix the PSS the same way. One way would be to re-clamp it, if the bellows tore, by sliding the bellows back beyond the tear and re-clamping to the shaft log. You'd also need to slide the stainless rotor back to meet the bellows. These bellows are quite long when not compressed and may give you enough room to do this. On the other hand the rubber hose on a traditional stuffing box is quite short and filled with the male end of the stuffing box which would not allow you to move it much. Another way would be to wrap it in saran wrap about ten times then go over that with electrical tape or self adhering rigging tape then duct tape over that. Any of these methods should get you into port but I would not worry about it. Insurance claims show that far more boats sink due to traditional stuffing boxes than PSS types..
A PSS fish story
I didn't want to title my response "PSS can fail", because I'm a fan of the product. Liked it so much I bought a second one. Here's why. Hunter 290's have a blower in the engine compartment; no reason why other than to maybe release some heat. The blower has a 4" white hose to the vent, exactly the same as the hose used in a clothes dryer. It has a small wire embedded in it that loops around and around to keep the hose open. Someone never clamped the hose to the blower. Over time, the hose fell off and landed on the shaft. Which was turning at the time. And proceeded to wrap itself around my PSS. And then it proceeded to slice the rubber bellows to shreds. Water started pouring in. The "fishy" part of the story: the wire wrapped itself so tightly around the PSS and shaft that it actually re-sealed the shaft. By the time I went below, it was only dripping (the amount of water and plastic all over the place showed what had happened before the shaft resealed). Albeit, with a massive mess of wire. We hauled the boat, pulled the shaft (there was no unwinding the mess). Despite the failure, I replaced the PSS with another one (just can't beat a dry bilge). I replaced the blower hose with aluminum hose and fastened it securely. So the point? I think Ross and MaineSail may be onto the solution - if PSS ever does fail, wrapping something around the shaft is likely the only way to keep the boat afloat. Keep the engine speed down. There is an additional risk with the PSS (the rubber bellows have to be able to compress, so the rubber is not the same as a standard stuffing box). But as one who's seen a failure, I still use a PSS.
I didn't want to title my response "PSS can fail", because I'm a fan of the product. Liked it so much I bought a second one. Here's why. Hunter 290's have a blower in the engine compartment; no reason why other than to maybe release some heat. The blower has a 4" white hose to the vent, exactly the same as the hose used in a clothes dryer. It has a small wire embedded in it that loops around and around to keep the hose open. Someone never clamped the hose to the blower. Over time, the hose fell off and landed on the shaft. Which was turning at the time. And proceeded to wrap itself around my PSS. And then it proceeded to slice the rubber bellows to shreds. Water started pouring in. The "fishy" part of the story: the wire wrapped itself so tightly around the PSS and shaft that it actually re-sealed the shaft. By the time I went below, it was only dripping (the amount of water and plastic all over the place showed what had happened before the shaft resealed). Albeit, with a massive mess of wire. We hauled the boat, pulled the shaft (there was no unwinding the mess). Despite the failure, I replaced the PSS with another one (just can't beat a dry bilge). I replaced the blower hose with aluminum hose and fastened it securely. So the point? I think Ross and MaineSail may be onto the solution - if PSS ever does fail, wrapping something around the shaft is likely the only way to keep the boat afloat. Keep the engine speed down. There is an additional risk with the PSS (the rubber bellows have to be able to compress, so the rubber is not the same as a standard stuffing box). But as one who's seen a failure, I still use a PSS.
That's a random..
That's a random event but like anything on a boat if it can happen it eventually will happen. Unfortunately there is nothing on a boat that is 100% fool proof and will guarantee to keep your boat on top of the water. I actually saw a boat that sunk because galvanic corrosion ate the pin for the speed transducer. By the time they noticed it the boat had to much water in it to figure out where it was coming from and down she went. They found pieces of the stainless steel speed log pin in the bilge when they raised the boat.. If it can it eventually will if your not careful!
That's a random event but like anything on a boat if it can happen it eventually will happen. Unfortunately there is nothing on a boat that is 100% fool proof and will guarantee to keep your boat on top of the water. I actually saw a boat that sunk because galvanic corrosion ate the pin for the speed transducer. By the time they noticed it the boat had to much water in it to figure out where it was coming from and down she went. They found pieces of the stainless steel speed log pin in the bilge when they raised the boat.. If it can it eventually will if your not careful!
It happened to me
I had a Deep Sea Seal version with a much thinner bellows and these were mounted on the shaft whilst the carbon face was on the log tube. This is the opposite to the PSS and I think the PSS is far safer. The boat had not been used for months and my boat just went aground in soft mud at low water springs. On the day I had an important meeting in a Cowes yacht club about 5 miles away across calm water. I laid my smart blazer on the bunk and my smart shoes on the cabin sole. The boat was just aground so I gave it full throttle to back out of the slip and then proceeded to go to my meeting. Half way there I chanced to look down into the cabin and was flabbergasted to see my shoes come floating towards me in 6" of water. Clearly something was wrong. Try as I might I could not find the leak. The entry point was was under water and I could not tell where the water was coming in. I grabbed the bilge pump handle, set the boat on autopilot and went hell for leather to Cowes. I now had time to think but decided not to call the Coastguard - mainly because of the ridicule I would get later!! At some point I realised I was gaining on the water level so swept up to the yacht club pontoon, made fast, gave some verbal to the Bosun who said I was not allowed to moor there and set to to find the leak. Yes, as I had backed out of the slip the engine had been pulled backwards, the stainless/carbon seal had fused, the bellows had turned on the shaft and pushed 1/2" up the shaft allowing water to flood in. That boat had no automatic bilge pump. Lessons learned:- 1) A leak below the bilge water is very difficult, perhaps impossible to locate. 2) A manual bilge pump can just about keep up with this leak - so long as your strength lasts! 3) Pride comes before a fall. When I installed the new PSS on my H376 I put a dimple in the shaft for the point of the grub screw. I added a second grub screw on top of the first AND I put a second jubilee clip on the shaft to prevent the disk from backing off.
I had a Deep Sea Seal version with a much thinner bellows and these were mounted on the shaft whilst the carbon face was on the log tube. This is the opposite to the PSS and I think the PSS is far safer. The boat had not been used for months and my boat just went aground in soft mud at low water springs. On the day I had an important meeting in a Cowes yacht club about 5 miles away across calm water. I laid my smart blazer on the bunk and my smart shoes on the cabin sole. The boat was just aground so I gave it full throttle to back out of the slip and then proceeded to go to my meeting. Half way there I chanced to look down into the cabin and was flabbergasted to see my shoes come floating towards me in 6" of water. Clearly something was wrong. Try as I might I could not find the leak. The entry point was was under water and I could not tell where the water was coming in. I grabbed the bilge pump handle, set the boat on autopilot and went hell for leather to Cowes. I now had time to think but decided not to call the Coastguard - mainly because of the ridicule I would get later!! At some point I realised I was gaining on the water level so swept up to the yacht club pontoon, made fast, gave some verbal to the Bosun who said I was not allowed to moor there and set to to find the leak. Yes, as I had backed out of the slip the engine had been pulled backwards, the stainless/carbon seal had fused, the bellows had turned on the shaft and pushed 1/2" up the shaft allowing water to flood in. That boat had no automatic bilge pump. Lessons learned:- 1) A leak below the bilge water is very difficult, perhaps impossible to locate. 2) A manual bilge pump can just about keep up with this leak - so long as your strength lasts! 3) Pride comes before a fall. When I installed the new PSS on my H376 I put a dimple in the shaft for the point of the grub screw. I added a second grub screw on top of the first AND I put a second jubilee clip on the shaft to prevent the disk from backing off.
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