Dripless Propshaft Seal - NOT!

[Plevier]

On my berth I get currents up to about 5kts and for a long time couldn't understand why I had a pint or two of water in the bilge when it had been left a week or so. It was the prop turning and the Volvo seal dripping a bit - leaving it in gear after that fixed it. Oddly it didn't drip at all with engine running but it seeped through with very slow rotation.
Now I have a feathering prop so no problem.
Certainly don't fancy 35kts current

 

[Tranona]

The Volvo seal installation on Beneteaus does indeed have a water feed behind the seal into the stern tube. This ensures that there is always water in the seal when running.

The seal construction has a portion of fluted rubber bearing rather like a cutless and two lip seals in the tapered end. The seals are watercooled at the back and lubricated with grease. Normally they only need grease once a year. If the seal is leaking it is either these seals that have worn or the clamp holding the seal onto the stern tube is loose. Highly unlikely to be caused by any debris as it would have to get past the cutless at the aft end of the shaft log. Neither is it likely to be wear from the prop turning as water would still be keeping it cool. Wear can occur if the boat is run in shallow sandy water for any length of time.

 

[Ric]

Perhaps could have ingressed by the rudder post in water speed like that. Check the whole rear end of the boat for signs of water ingress.

 

[David2452]

Doesnt sound like a Volvo seal either because they do not have water flows into them and in any case they are grease lubricated

Beneteau use water lubrication on the VP seals by tapping in an inlet in the mount on a number of models.

 

[wotayottie]

watayottie,

It's definately a Volvo Penta seal, it's described in detail in the manual and I have googled it as well. Apparently there is two seals on it one lubricated by water and the other by grease on assembly. There is a water inlet from a screend through hull fitting which appears to be at such an angle that it catches the slipstream water and sends it, via a hose into the stern tube. Thats about where my understanding peters out.

The prop end of the boat was facing away from the water flow and while your suggestion is certainly plausible, hopefully its not what happened. The boat is going to come out of the water in any case, a careful inspection of all the surrounding area will also be done. Another problem is that there are so many boats needing lift out and repair that lift time and hardstand space will become very scarce.

I've bodgied up a fix to stop the water leaking in and have gained plenty of time to do the work, I guess the major reason for my original question is would that be a reasonable insurance claim?

Cheers

Is this https://www.google.co.uk/search?q=volvo+penta+shaft+seal&hl=en&client=firefox-a&hs=Qb9&tbo=u&rls=org.mozilla:en-GBfficial&tbm=isch&source=univ&sa=X&ei=mx0QUcGYE6mU0QWStoCIDw&ved=0CFcQsAQ&biw=1920&bih=917#imgrc=G19eK5sXMgztbM%3A%3BRH7R10RBNL_kVM%3Bhttp%253A%252F%252Fwww.ropewalkmarine.com%252Fimages%252Fthumbs%252F0003430_300.jpg%3Bhttp%253A%252F%252Fwww.ropewalkmarine.com%252Fproducts%252F23603-828254.aspx%3B300%3B261 what it looks like because this is the Volvo shaft seal that I have on my boat and the only one sold over here? Suppose it might be different in Oz but I doubt it.

I would certainly have thought it a reasonable insurance claim though if it is only the shaft you might get into areas of wear and tear. But I would unform the insurance company without quantifying a claim untikl the boat is lifted - after all if you are right and it is just prop rotation that has caused the problem, what has this done to the gearbox output bearing and seal. What has it donbe to the shaft since its the hard bit that wears most when soft rubs against hard.

 

[HunterWanderer]

Beneteau fit a vent pipe to the top of the stern tube to ensure the seal runs wet. This isn't a lubrication pipe. (Beware where this pipe vents as it can squirt seawater when in rough seas.)

Do you grease it every year?

 

[David2452]

Beneteau fit a vent pipe to the top of the stern tube to ensure the seal runs wet. This isn't a lubrication pipe. (Beware where this pipe vents as it can squirt seawater when in rough seas.)

Do you grease it every year?

Beneteau actually use both methods depending on the vessel type, some are pressure and some are vents, it's easy to tell which by following the tube. They are designated to be replaced at five year intervals, though I know most people don't know or don't bother but if it has not been then any insurance claim might be on thin ice.

 

[Professor Longhair]

A lot of good feedback thanks folks.

The pipe on my stern tube runs from an inlet on the right side of the tube through a ball valve to the top of the stern tube itself, well aft of the seal assembly.
There is no pump but the design/placement of the inlet scoop seems to encourage flow when under way.

I had read in the boat manual that the seal was designed to be replaced every five years, the boats 10 years old and i'm not aware of it being replaced so it looks like a maintenance issue rather than damage. In any case I notified the insurance company today and will haul out and get the work done in the coming weeks.

Cheers

 

[sailorman]

40 kts wind i assume, i dont believe the river would flow @ that rate

This is a tow i photographed @ probably 8 >10kts

Norman,

Mate, reported speeds of up to 40kts but I wasn't there at that time due to being stranded by flooding elsewhere.

Cheers

 

[Professor Longhair]

As I said earlier I wasn't there at the peak of the current, however when I did get there it was running way faster than the pic above. Think the marina pontoons turning almost 90 degrees with water cascading over them, the roller followers sheared off. The marina was full of a roaring noise, boats were thrashing about, straining at their lines. A number of pontoon sections broke away sending the sections and the boats tied to them careening off down the river and out to sea or in some cases into other sections of the marina. We had at least three boats sunk in the marina with a number more damaged and at least 20 swept out into the sea, most to be dashed back against the rocks or if lucky the sandy shore.