Can anyone give me some advice on when to replace the PSS dripless stern seal on a Hunter 410 with 2000 hours on the motor? We have recently taken our vessel out of a charter fleet. Since doing this, we have been constantly fixing things left undone by the charter company. The second time we went out sailing, after two hours under sail, and in 50 metres of water, the bilge alarm went off. On investigation we found that a vast amount of water was pouring into the boat through the stern gland!!!! After quite a few anxious minutes, we discovered that the rotor on the seal had slipped up the drive shaft and the water was pouring in between the bellows and the rotor. We found the inner allen screws were loose allowing the rotor to move. Luckily we had allen keys on board and were able to adjust the seal before we sank, as the bilge pump could not keep up with the flow of water. We shudder to think what would have happened if the boat was in the charge of a charterer when this happened. We have decided that if you love your boat, you don't lease it to a charter company. Things seem to be okay now, but we'd like to be certain before we go any further afield. Should we look into the problem any further and is there anything else that should be replaced in this area? Gary & Judith
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How Many Hours On The Seal?
You can check directly with the manufacturer, but they recommend replacing the carbon disk and adjusting the bellows or replacing it at some hours, not sure how many. I intend to do it next haul with 1100 hours. The collar is supposed to have two set screws at each location. One seats on the shaft. The other screws down upon it and operates as a locking screw. It needs an anti-vibration additive on it as well. And, if the originals loosened up, the set screws should be replaced since the point will be blunted. Sounds like they loosened it once for service and failed to properly reset it. Some people put a hose clamp in front of the collar for peace of mind and double redundancy. Rick D.
You can check directly with the manufacturer, but they recommend replacing the carbon disk and adjusting the bellows or replacing it at some hours, not sure how many. I intend to do it next haul with 1100 hours. The collar is supposed to have two set screws at each location. One seats on the shaft. The other screws down upon it and operates as a locking screw. It needs an anti-vibration additive on it as well. And, if the originals loosened up, the set screws should be replaced since the point will be blunted. Sounds like they loosened it once for service and failed to properly reset it. Some people put a hose clamp in front of the collar for peace of mind and double redundancy. Rick D.
Conventional Stuffing Box Is My Choice
Call me a traditionalist, but I fooled around with bellows type dripless boxes on two prior boats and went back to a conventional type where everthing is visible and straightforward.Even on my 35.5 which I now have I have the old rubber hose and clamp type stuffing box. So it drips a bit, no big deal. Sometimes low tech is the better choice. Fred Miller S/V M Squared
Call me a traditionalist, but I fooled around with bellows type dripless boxes on two prior boats and went back to a conventional type where everthing is visible and straightforward.Even on my 35.5 which I now have I have the old rubber hose and clamp type stuffing box. So it drips a bit, no big deal. Sometimes low tech is the better choice. Fred Miller S/V M Squared
Superb Simplicity
To me the PSS is perfect simplicity, and I wouldn't even consider giving it up. It does however, just like any other mechanical system on the boat that retains integrity, requires proper installation and a modicum of attention. Proper installation? Simple as can be. Slide the stainless collar into it's intended position WITHOUT THE O-RINGS in place. Run the two set screws down onto the shaft to mark the shaft. Loosen, and remove the collar and install new o-rings. Using a small fine file make slight flats on the shaft where it was marked by the screws, providing smooth chamfers in forward and aft directions. Polish the chamfers with emery cloth. This is done to prevent the divot raised by the set screws from damaging the internal o-rings if and when the collar is moved. Slide the collar into place with o-rings in place. Tighten the inner set screws tight, back them out, then retighten firmly. PLEASE don't question me on this one, just DO IT. You can use thread locking compound if you like but I prefer to rely on proper assembly. Lastly, snug the second set screws in over the first ones. Installing this way you will not experience problems. Yes, you can (and I did) add redundancy by putting a hose clamp in front of the collar as well as around it's circumference to make sure the set screws can't back out. Mine gets an occasional visual and/or physical inspection, that is I run a finger under the mating point to see how wet it is. Very little at most, by the way. My question to Gary is: Did you personaly check out these all important systems on the boat you paid for? I didn't think so. It aint your boat till you've sweated and bled on it. When you've done that you'll KNOW the boat in and out and have no concerns over the systems because you'll know exactly the competence of the mechanic.
To me the PSS is perfect simplicity, and I wouldn't even consider giving it up. It does however, just like any other mechanical system on the boat that retains integrity, requires proper installation and a modicum of attention. Proper installation? Simple as can be. Slide the stainless collar into it's intended position WITHOUT THE O-RINGS in place. Run the two set screws down onto the shaft to mark the shaft. Loosen, and remove the collar and install new o-rings. Using a small fine file make slight flats on the shaft where it was marked by the screws, providing smooth chamfers in forward and aft directions. Polish the chamfers with emery cloth. This is done to prevent the divot raised by the set screws from damaging the internal o-rings if and when the collar is moved. Slide the collar into place with o-rings in place. Tighten the inner set screws tight, back them out, then retighten firmly. PLEASE don't question me on this one, just DO IT. You can use thread locking compound if you like but I prefer to rely on proper assembly. Lastly, snug the second set screws in over the first ones. Installing this way you will not experience problems. Yes, you can (and I did) add redundancy by putting a hose clamp in front of the collar as well as around it's circumference to make sure the set screws can't back out. Mine gets an occasional visual and/or physical inspection, that is I run a finger under the mating point to see how wet it is. Very little at most, by the way. My question to Gary is: Did you personaly check out these all important systems on the boat you paid for? I didn't think so. It aint your boat till you've sweated and bled on it. When you've done that you'll KNOW the boat in and out and have no concerns over the systems because you'll know exactly the competence of the mechanic.
Shaft seal
I agree with Fred, I have had two so called dripless systems and while one gave me no problems ( except loosening set screws ) I went back to the conventional stuffing box with dripless packing. No problems yet.
I agree with Fred, I have had two so called dripless systems and while one gave me no problems ( except loosening set screws ) I went back to the conventional stuffing box with dripless packing. No problems yet.
Thanks everyone
Thanks for your replies to our question. Sam, we are now in the process of checking EVERYTHING as you suggest. This boat has been ours from new, but leased to a charter company who professed to maintain it "better than anyone else". We now know that this is far from the truth, and hopefully we can avert any more near disasters by doing all the checks and balances ourselves. Does anyone have the current address for PYI (the manufacturers of the PSS water lubricated stern shaft seal) as the address in the manual is out of date?
Thanks for your replies to our question. Sam, we are now in the process of checking EVERYTHING as you suggest. This boat has been ours from new, but leased to a charter company who professed to maintain it "better than anyone else". We now know that this is far from the truth, and hopefully we can avert any more near disasters by doing all the checks and balances ourselves. Does anyone have the current address for PYI (the manufacturers of the PSS water lubricated stern shaft seal) as the address in the manual is out of date?
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