Hi guys, back on deck after spending a couple of weeks 4wdriving around the Hervey Bay area and Fraser Island - an amazing place!
I have a bit of a problem with the through hull shaft seal - it's not leaking, but there is a black line that has appeared on the bilge matting. It seems to have been "flinging off" the mechanical seal.
I first noticed a whining sound when the engine revs were over 1800 rpm (I normally run at 1500 - 1600rpm). When in neutral there is no whining sound.
So I'm thinking the mechanical seal is wearing away and is in need of replacement. To do that, it would mean taking her out of the water I guess.
Can any of you knowledgeable people give me some idea if I am on the right track please?
I can probably post some pics if it helps.
Cheers!
Select to expand quoteNowandZen said..
Hi guys, back on deck after spending a couple of weeks 4wdriving around the Hervey Bay area and Fraser Island - an amazing place!
I have a bit of a problem with the through hull shaft seal - it's not leaking, but there is a black line that has appeared on the bilge matting. It seems to have been "flinging off" the mechanical seal.
I first noticed a whining sound when the engine revs were over 1800 rpm (I normally run at 1500 - 1600rpm). When in neutral there is no whining sound.
So I'm thinking the mechanical seal is wearing away and is in need of replacement. To do that, it would mean taking her out of the water I guess.
Can any of you knowledgeable people give me some idea if I am on the right track please?
I can probably post some pics if it helps.
Cheers!
Run a magnet over the black line. If you collect metal fuzz it probably is a dry bearing and the rollers are wearing out. If this is the case the boat has to come out. Look at it in a positive way, you'll be able to get the barnacles off the hull.
Is it a PSS seal or a different design for a PSS you could pull back on the transmission side and see it there is sea water there for cooling is the cutlass bearing ok not to much wear? Also what Lady jane has said make sense also.
Do you have a clear hose on the PSS seal ?
Below the hose barb where the air bleed hose fits is there a visual of cooling water . at the hose end
Or could you have picked up some fishing line at the prop
Sounds like carbon from a dry mechanical seal. I am afraid the magnet won't tell you much because there is unlikely to be magnetic material there. You can try pulling the bellows back until you get a bleed.
If you need to haul out Fishermans Wharf Marina in Urangan have great rates.
Maybe check your gearbox oil level while you're down there and stop whining Now and Zen get on with it 
Select to expand quoteHG02 said..
Maybe check your gearbox oil level while you're down there and stop whining Now and Zen get on with it
Hah ha!
Gearbox all good HG.
Select to expand quoteNowandZen said..HG02 said..
Maybe check your gearbox oil level while you're down there and stop whining Now and Zen get on with it
Hah ha!
Gearbox all good HG.
just a thought worth a look 
Select to expand quotePhoenixStar said..
Sounds like carbon from a dry mechanical seal. I am afraid the magnet won't tell you much because there is unlikely to be magnetic material there. You can try pulling the bellows back until you get a bleed.
If you need to haul out Fishermans Wharf Marina in Urangan have great rates.
Yes you are right it is a dry mech seal - no seal water.
It looks like a PSS seal, but I don't know what the 1/2 in the second photo means because it is obviously bigger than half inch.
I pulled the bellows back a couple of weeks ago hoping it would flush some gunk through, but the problem persists.
The thing is I don't know how to tell if it is past it's use-by date or not.
Select to expand quoteNowandZen said..PhoenixStar said..
Sounds like carbon from a dry mechanical seal. I am afraid the magnet won't tell you much because there is unlikely to be magnetic material there. You can try pulling the bellows back until you get a bleed.
If you need to haul out Fishermans Wharf Marina in Urangan have great rates.
Yes you are right it is a dry mech seal - no seal water.
It looks like a PSS seal, but I don't know what the 1/2 in the second photo means because it is obviously bigger than half inch.
I pulled the bellows back a couple of weeks ago hoping it would flush some gunk through, but the problem persists.
The thing is I don't know how to tell if it is past it's use-by date or not.
Select to expand quoteNowandZen said..PhoenixStar said..
Sounds like carbon from a dry mechanical seal. I am afraid the magnet won't tell you much because there is unlikely to be magnetic material there. You can try pulling the bellows back until you get a bleed.
If you need to haul out Fishermans Wharf Marina in Urangan have great rates.
Yes you are right it is a dry mech seal - no seal water.
It looks like a PSS seal, but I don't know what the 1/2 in the second photo means because it is obviously bigger than half inch.
I pulled the bellows back a couple of weeks ago hoping it would flush some gunk through, but the problem persists.
The thing is I don't know how to tell if it is past it's use-by date or not.
In that first photo, is the shaft alignment a bit out or is that an optical illusion? It just looks like the seal is bearing harder on the port side, maybe rubbing on the outer dry section of the carbon rather than the center.
I see a 1 to the left of the 1/2( is your prop shaft 1/1/2 can't quite make out the word on the retaining ring
this is what it should look like if its a PSS seal
You really should have two grub screws inserted in the lock ring held in with loctite .
I have read 7 years and they should be inspected and the seal replaced
Perhaps its an early one I have a feeling Ramona has a early PSS seal I can sort of remember him saying something ages ago about it The current version takes water either from the cutlass bearing or water from the engine cooling system if its from the cutlass bearing you attach a hose to the hose barb and fix it above the water line so water can enter and cool the mechanical seal via the cutlass bearing
http://www.shaftseal.com/en/product_categories/300000001?page=2
The link below is for rudder shaft seals
www.shaftseal.com/en/categories/300000003
Id lift her out and buy a new PSS seal kit and install it I love spending your money because I'm jealous of where you are and I'm stuck in winter
You just have to measure the prop shaft and also the the hull tube that the bellows is hose clamped to
The stainless steel rotor face is most likely pitted with corrosion and it is grinding away the static carbon seal face.
we currently have a dripless seal on our boat, and recently a boat mechanic recommended going back to a stuffing box type seal with teflon packing.
his rationale was that the dripless seals are not serviceable, whereas you can repack a stuffing box type seal without a haul out.
what are people's thoughts on this?
Select to expand quotefishmonkey said..
we currently have a dripless seal on our boat, and recently a boat mechanic recommended going back to a stuffing box type seal with teflon packing.
his rationale was that the dripless seals are not serviceable, whereas you can repack a stuffing box type seal without a haul out.
what are people's thoughts on this?
if you like having a wet bilge
a PSS seal will last around 7 years and then needs a service Id rather have a dry bilge make a healthier boat and with a stuffing box after every use the teflon needs to be grease and when it drips to much you have to tighten it up on a regular basis its all about choices and how you feel
I think I deleted the before photo I was far to embarrassed to show any one
it will stay like that while I'm alive
the before shot would have looked like bath water that had not been changed for years for a family of 13 kids 
below for my one of the better things Ive done to my boat its all about choice and what you want
Im happy and that what counts for me
Select to expand quotefishmonkey said..
we currently have a dripless seal on our boat, and recently a boat mechanic recommended going back to a stuffing box type seal with teflon packing.
his rationale was that the dripless seals are not serviceable, whereas you can repack a stuffing box type seal without a haul out.
what are people's thoughts on this?
If you have access to a marina with haul out facility all year long then a dripless seal will keep the bilge clean. For long voyages I would recommend the packing box seal which is easy to maintain in rough sea. Most of the time 1/8 of a turn on the seal cap will fix a leak. I have stainless trays under the seals with a drain hose running into the aft bilge pump box, to avoid that smelly bath water. A bag of Teflon shavings is 80 Euro, cheaper than hauling, specially a large beam boat.
Nothing wrong with stuffing box and nothing wrong with the Volvo double lip seals, but the best solution I saw was on a ketch in Maryborough, he had bearings top and bottom in his shaft tube and double lipped seals top and bottom. He flooded the tube with oil and had a riser and tiny header tank above the waterline. It was a forever setup.
Select to expand quoteLadyJane said..fishmonkey said..
we currently have a dripless seal on our boat, and recently a boat mechanic recommended going back to a stuffing box type seal with teflon packing.
his rationale was that the dripless seals are not serviceable, whereas you can repack a stuffing box type seal without a haul out.
what are people's thoughts on this?
If you have access to a marina with haul out facility all year long then a dripless seal will keep the bilge clean. For long voyages I would recommend the packing box seal which is easy to maintain in rough sea. Most of the time 1/8 of a turn on the seal cap will fix a leak. I have stainless trays under the seals with a drain hose running into the aft bilge pump box, to avoid that smelly bath water. A bag of Teflon shavings is 80 Euro, cheaper than hauling, specially a large beam boat.
i agree Teflon packing gland might drip occasionally but chance of a catastrophic failure nearly nill the same cant be said for a dripless seal
Select to expand quotePhoenixStar said..
Nothing wrong with stuffing box and nothing wrong with the Volvo double lip seals, but the best solution I saw was on a ketch in Maryborough, he had bearings top and bottom in his shaft tube and double lipped seals top and bottom. He flooded the tube with oil and had a riser and tiny header tank above the waterline. It was a forever setup.
The problem is the salt erodes the sea side lip and gets trapped between the lips, who said stainless steel shaft do not corrode? In this particular exemple the lip seal gets 0.9 bar pressure of sea water.
Select to expand quoteLadyJane said..PhoenixStar said..
Nothing wrong with stuffing box and nothing wrong with the Volvo double lip seals, but the best solution I saw was on a ketch in Maryborough, he had bearings top and bottom in his shaft tube and double lipped seals top and bottom. He flooded the tube with oil and had a riser and tiny header tank above the waterline. It was a forever setup.
The problem is the salt erodes the sea side lip and gets trapped between the lips, who said stainless steel shaft do not corrode? In this particular exemple the lip seal gets 0.9 bar pressure of sea water.
That's why he uses a header tank - slight oil pressure inside the tube. He also replaces the stainless coil in the seal with an o ring.
Select to expand quotePhoenixStar said..LadyJane said..PhoenixStar said..
Nothing wrong with stuffing box and nothing wrong with the Volvo double lip seals, but the best solution I saw was on a ketch in Maryborough, he had bearings top and bottom in his shaft tube and double lipped seals top and bottom. He flooded the tube with oil and had a riser and tiny header tank above the waterline. It was a forever setup.
The problem is the salt erodes the sea side lip and gets trapped between the lips, who said stainless steel shaft do not corrode? In this particular exemple the lip seal gets 0.9 bar pressure of sea water.
That's why he uses a header tank - slight oil pressure inside the tube. He also replaces the stainless coil in the seal with an o ring.
The header tank would have to be at list a metre above the water line to equalize the pressure in the shaft tube. Probably more since oil is lighter than water. Since lip seals don't last forever that ketch may end up with those lovely rainbow colours around its WL. And if the lip seal does its job, the oil will not get in between the lips, the corrosion will still set in.
Select to expand quotePhoenixStar said...LadyJane said..PhoenixStar said..
Nothing wrong with stuffing box and nothing wrong with the Volvo double lip seals, but the best solution I saw was on a ketch in Maryborough, he had bearings top and bottom in his shaft tube and double lipped seals top and bottom. He flooded the tube with oil and had a riser and tiny header tank above the waterline. It was a forever setup.
The problem is the salt erodes the sea side lip and gets trapped between the lips, who said stainless steel shaft do not corrode? In this particular exemple the lip seal gets 0.9 bar pressure of sea water.
That's why he uses a header tank - slight oil pressure inside the tube. He also replaces the stainless coil in the seal with an o ring.
if you can find them some seals Bukh sell have bronze springs on there double lipped seals
Select to expand quoteNowandZen said..PhoenixStar said..
Sounds like carbon from a dry mechanical seal. I am afraid the magnet won't tell you much because there is unlikely to be magnetic material there. You can try pulling the bellows back until you get a bleed.
If you need to haul out Fishermans Wharf Marina in Urangan have great rates.
Yes you are right it is a dry mech seal - no seal water.
It looks like a PSS seal, but I don't know what the 1/2 in the second photo means because it is obviously bigger than half inch.
I pulled the bellows back a couple of weeks ago hoping it would flush some gunk through, but the problem persists.
The thing is I don't know how to tell if it is past it's use-by date or not.
See that thread on the lower RHS of the bottom photo. Shouldnt there be a a locking second screw in that hole? Also, what is the device between the seal and the gearbox? Rubber or gear type flexible coupling?
Lady Jane, I agree with your comments on the oil filled stern tube. However the pressure would be circa 9 kPa or 0.09Bar. What do you do with the teflon shavings? Are they in the form of a teflon packing strip?
IMHO the issue of the classic stuffing box vs mechanical seal is also one of access. If it is easy and quick to get to the stuffing box nut, that would help. There are videos on the net of people changing seals on the water, but it is hairy, and even more so at sea.
What ever your personal preferences
either stuffing box or some other sealing design maintance has to be done
Looking at now and Zen seal says to me if it was a pas seal and they have redesigned it
I would have wondered how old it was
I Kwong how old my seal is and if in a few year time I was heading a long way off shore it would be replaced as a preventive maintance
much the same way as I do with work
No down time
To me a double lipped seal was designed for retaining oil inside some mechanical device not to keep water out
I looked at all the designs and just like a high volume pump at any council water supply the pumps have mechanical seals
that's why I have a PSS seal fitted
stuffing boxes that I've seen usually fitted to some cockies small irrigation pum hanging off a tractor
it's all personal choice
eventually every double lipped seal drives groove into the shaft its sealing against
in machinery or autos it means a speedy sleeve or shaft replacement
The collar on the PSS seal has two O rings on installation some rudder grease or vasoline helps seal the orings and once that collar is locked by the grub screws to retain the collar in the recommended position with two grub screws in each thread of the collar and also retained with loctite should not move you can also fit an extra collar as a precaution on the gear box side
the carbon seal with its spring pressure assists the carbon sealing system
Also the carbon seals surface area it at least 100 times larger than a double lip seal and it doesn't rub against the prop shaft
b
I'm happy with my choice
fish monkey do you have some spare pump packing tucked away on board ?
in a couple o years time I'll buy a spare PSS seal kit and have it on board maybe it 4 years time I will fit it and keep the old one as a spare
in an emergence in the water I know I could fit it and have a wet bilge for a short time
Hi Yara, shavings is probably the wrong word, just an old expression no longer appropriate but the principle is the same.
I use PTFE Teflon balls for elasticity in compression between the stuffing box cover and the Teflon pressure plate. Between the pressure plate and the back of the box I use braids made out of staple (what I wrongly call shavings) carbon fibres. This has a very good lubricating performance and requires less gland load and does not damage the shaft. Please don't get me wrong, I am not against any other type of seal, what I am saying is that this is the most practical and economical way for me only, to repair a leaking shaft at sea. I had to screw the cap 1/8 of a turn once in two and a half years. It works for me and
"I am happy with my choice" 
