Which Shaft Seal??

[Tranona]

The debate on the merits of different shaft seals will run and run. The face to face seals such as PSS and Tides rely on the bellows pressure keeping the two faces in contact with eachother. They also require water to keep them cool, hence the need for injecting cooling water on high power/speed applications. Potential problems are the faces wearing or not maintaining pressure, although current designs with the bellows on the fixed part of the stern tube minimise this. Some earlier designs had the bellows on the shaft and were known to shift with water pressure coming up the stern tube. One example was on a boat that surfed and the water pressure was enough to separate the sealing faces.

To my mind for a normal yacht auxiliary the Volvo seal has a lot going for it. Simple, provides good support for the shaft, never leaks and lasts a long time. Cheaper than alternatives as well. only drawback seems to be that not all stern tubes are the right diameter, but on my installation it was a simple machining job to turn the housing down.

Not familiar with the Radice version. Their website only shows face type seals, but a better way of getting grease into the lip seals would be an improvement.

 

[MoodySabre]

No - the tides seal does not have two faces like the PSS. Inside the bellows is a solid rubber tube the looks like a cutless bearing and that makes the seal at the end stay in line. To that extent it is more like the Volvo seal. I assume the seal is nitril (?). The water feed stops it all drying out and wearing, compared to Volvo which needs a bit grease each year. The bellows make it more flexible for fitting sizes.

 

[Frankklose]

The radice seal is sold over here by ALLPA www.allpa.nl
Its in the 2008 katalog. I know that many dealers in the UK import stuff from ALLPA in the Netherlands.

 

[Robin]

I'll add another vote for the PSS seal and a big thumbs down for the Deep Sea Seal that it replaced on our boat. The PSS is a much sturdier product and does exactly what it says on the box. In our case the local dealer would only stock the PSS version with a hose attachment which for normal speed use is used to take off a vent hose well above the waterline but for high speed use would be the feed for water pumped in from the engine. Used as a vent this allows a small head of water above the seal which both keeps the seal faces lubricated and vents off any air when the boat is relaunched after a period ashore. There is a PSS version without the hose fitting but as far as I can see it's only possible advantage is that it reduces the overall length of the seal very slightly, if shaft space is a problem between seal and coupling, there surely can be no real difference in cost.

 

[cmedsailor]

Is there any installation procedure for the Volvo seal somewhere in the internet?
Thanks

 

[jimg]

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To my mind for a normal yacht auxiliary the Volvo seal has a lot going for it. Simple, provides good support for the shaft, never leaks and lasts a long time.

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Works fine in high speed mobo's as well. Never had a problem after hundred's of hours running.