Dripless Shaft seals - anyone done this?

Skybolt

Skybolt

Well-Known Member
Nov 11, 2014
6,452
Kent Narrows, MD
Boat Info
Reel Nauti
460 EC
Engines
Detroit 6v92TA
(Low profile's)
Alison Gears
Westerbeke
12.5kw Genset
Tides Marine Sureseal is a far superior seal. Not prone to catastrophic failure and you can carry a spare seal right on the shaft in front of the seal assembly. 15 minutes to change seal with very little leakage.
 
I put Tides seals on a 390EC several years ago. The process is exactly as replacing a complete seal assembly except the part where you have to polish the shaft. The shaft where the seal runs has to be clean and without any grooves or scratches with a final finish almost like a mirror.
 
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I just installed the Lasdrop Gen ll seals. The quality of the manufacture and design in my opinion make these the superior seal. When you look at the dominant failure modes of the other designs, the Gen ll design does not fall into those groups. I like the ridged installation of the static face as opposed to a bellows type. The seal face is actually mounted on a floating stainless spring rotating on a ball bearing gimble which allows for a great deal of misalignment (if necessary) ensuring the seal faces are always in contact and parallel (stay aligned). Also the seal face is clamped to the shaft and does not rely on set screws which have a habit of backing off. When first commissioned they started up dry and have remained bone dry. I've got about 50 hrs on them, which I know in the grand scheme is not much, but it is very gratifying to see those bilges dry!

No problems yet... Knock on wood! But I really like this design. It makes good sense. I recommend you give them a hard look. I'm retired now, but in a past life my job was to develop/facilitate maintenance plans for equipment at a manufacturing site. There was a lot of looking into failure modes, probability, cost, risk, etc. If a plan could not be developed we would elect to either re-engineer the asset to eliminate failure modes or just decide that we'd allow the failure due to low consequence (run to failure). This process worked pretty well for us making our location one of the most reliable in the world. I think Lasdrop has done some of the same.
 
Thank you for all of the responses. I am leaning towards Paul's recommendation as that is what I originally thought to use.

I am not sure I like "Oil Seal" type of dripless. I understand how they work with the water pressure and all, but oil seals always leak at some point.

The Lasdrop Gen II seals work very much like the P.S.S type which I have in my 340, and they never leaked ever - not a drop and no maintenance in over 10 yrs. Just light cleaning once in a while. I really like the mechanical interface of the carbon and Stainless steel faces.

Anyway right now it's ~15' here in Long Island, so I have a while until I can even think of doing this. I might tackle this in march before the boat goes back in. I am not looking forward to getting the couplings off of the 2" shaft. But it needs to be done, my port stuffing box has very little threads left as the collar is super sloppy and all of the packing is like cement.
 
But, the PSS type seas that rely on a sealing face running against a carbon follower are very un-forgiving in water containing sand or silt. They only work here in deep water boats that never churn up bottom debris when anchoring or docking. There is 1/2 a barrel full of them in our marina's shop area that were removed from boats whose owners preferred them on paper but found that they leak like a shower head if you accidentally feed them some sand in a shallow slip or anchorage. The Tides design is a lot more forgiving and will tolerate some grit. So consider more than just "I don't like the oil seal"……your environment is critical to your seal selection.
 
I did the changeover to the PSS system several years ago and I am very happy with them. I run in clean water, per Franks observations, I have not experienced anything like he describes. All I can tell you is whatever you decide, you will be much happier than you are with those stuffing boxes. And drier.
 
I hate to disagree with Frank but I do. The same silt/sand issue will also happen on a seal that runs against a shaft like the tides does. If sand silt get in the PSS, it will also get in the Tides and could mark your shaft as now the sand/silt is running between the seal and the shaft. I do not like seals that continuously run against a shaft like the Tides. I have seen many shaft that are grooved due the seal running on them and the only thing I can account that from is a weak shaft, aquamet 19 perhaps but who knows. I have not seen the Lasdrop and will take a look at them for sure. I currently have the PSS shaft and have no problems. AND from what I have seen from other boats at our marina, the problem is not the seal that leaks, it is the bellows that fails and leaks. Don't care how many seals you have on the shaft at that point, if the bellows leaks there is no quick fix.
 
fwebster said:
But, the PSS type seas that rely on a sealing face running against a carbon follower are very un-forgiving in water containing sand or silt. They only work here in deep water boats that never churn up bottom debris when anchoring or docking. ... So consider more than just "I don't like the oil seal"……your environment is critical to your seal selection.
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Valid point for sure, I guess your talking about when your backing down into your slip? Not sure how otherwise you would have an issue. But isn't the water line there to help aid in keeping the seal clean as well as lubricated?

Now that's not to say I won't have an issue going forward, my other concern is that my shafts are not in the greatest shape from them being in a stuffing box situation their whole life. I am not sure I could polish them smooth enough for the seal, maybe though. But I would think the same issues are there with any kind of seal, sand scaring the seal surface. Something to definitely consider though, thanks.
 
You can likely position the tube so that the new seal doesn't ride in the "groove" of your old packing.
 
Other than backing down in a slip? Ever anchor in 5-6 ft of water in a boat swinging 24" props. Sand goes everywhere.

Tides handle sand/silt better because the housing has cooling water flushing it constantly. I replaced my tides seals a second time (the boat is 17 years old) after us in shallow Gulf waters 100% of that time. I decided I wanted to explore the options and spent some time examining the PSS seal system, finally getting to the point of calling their technical service people to ask questions that were not covered in the sales info. The guy on the phone had been there a number of years and could not give me anyone to call or talk to about their seas on the Gulf because they seem to sell thru distributors and have no ready access to retail customers. I explained my concern, i.e. early seal failure due to ingesting sand/silt during anchoring and docking. When I asked what their experience in such conditions had been the phone went silent and the guy eventually changed the subject with a neutral "We have seals all over that area" but he never addressed what happens when you ingest sand or silt.

I later went o the shop foreman who has helped me with my boats for 25 years and asked him about PSS seals. He is a guy who wastes no words and just said follow me. That is when we went out back and he pointed at the barrel 1/2 full of seals they had replaced. The carbon followers get scored and grooved by sand and sling water everywhere. They would have to run 100 years to self polish themselves. I suppose you could turn them in a lathe and re-face them, but you would have to uncouple the shaft and essentially spend the labor to replace the seal just to get the carbon follower off the shaft. The Tides seal design isn't perfect, but if you had sand/silt in the water was we do, it appears to the the least offensive choice.

As far as grooves go, I'e had lip seals on my boat for 1400 hours over 17 years. They have never been repositioned and I don't have grooves worn in the shaft.
 
The carbon/graphite ring assembly has two water injection ports. Both engines raw water cooling circuits are plumbed to each assembly. If for some reason you lose an engine, the other engine provides the necessary water flush.
 
I have Tides seals. Once they are installed, you pretty much forget them. However, I pull my cooling hoses off a couple of times a year and check the cooling flow just to be sure I haven't picked up any marine growth and I spray the lip seal once a month with silicone.
 
fwebster said:
I have Tides seals. Once they are installed, you pretty much forget them. However, I pull my cooling hoses off a couple of times a year and check the cooling flow just to be sure I haven't picked up any marine growth and I spray the lip seal once a month with silicone.
Click to expand...
What does the silicone spray do, Frank?
 
Kalee said:
The carbon/graphite ring assembly has two water injection ports. Both engines raw water cooling circuits are plumbed to each assembly. If for some reason you lose an engine, the other engine provides the necessary water flush.
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Thanks, I was not aware of the flushing I knew about the cooling in case of an engine failure. I had the Lasdrops on my boat and had the water lines connected, when I had purchased the boat the previous owner had different seals, with water connections, but not connected. I changed this and had the seals replaced and water connected.
 
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