Sail drive rubber bellows Volvo Penta

[Derek ide]

I know that they are recommended for replacement after 7 years. I have just changed mine after 11 years as I had to have work done on the sail drive itself. After some light cleaning the rubber bellows looked and felt like new. There was some light corrosion on the clamping plates but they were cleaned up and re-used.
Has anyone ever heard of a failure? I used to inspect mine very carefully and could not imagine a catastrophic failure. I would have been happy to continue until forced to change as I have been now.

 

[scottie]

Yes

 

[RichardS]

No

 

[JFowler]

No- mine is 15 years old & I’ve no plans to replace it.

 

[Martin_J]

Did you measure the thickness of the part of the diaphragm that has been clamped by the ring for the past eleven years?

I seem to think that even a few days after removal, although the rubber can still look good, it does get permanently compressed and stays that way. That I guess would leave less compression force on that part of the ring than when installed.

As you say though. They do appear tough - a bit like a car tyre. I've not tested it but I reckon you could stick a screwdriver through it and the toughness of the rubber would pretty much reseal the hole (although it would do that better in its younger years rather than when maybe fifteen years old).

 

[Derek ide]

Did you measure the thickness of the part of the diaphragm that has been clamped by the ring for the past eleven years?

I seem to think that even a few days after removal, although the rubber can still look good, it does get permanently compressed and stays that way. That I guess would leave less compression force on that part of the ring than when installed.

As you say though. They do appear tough - a bit like a car tyre. I've not tested it but I reckon you could stick a screwdriver through it and the toughness of the rubber would pretty much reseal the hole (although it would do that better in its younger years rather than when maybe fifteen years old).

You would have to have a sharp screwdriver and a strong arm . There is no way I could push a screwdriver through this one .
The flange does not appear compressed. I hope this gives you confidence in yours. Just keep an eye on it.

 

[pvb]

The problem is that, in the unlikely event that it were to fail, an insurance claim might be refused on the grounds that the recommended maintenance hadn't been carried out.

Mine's 7 years old and I'm getting it replaced this month.

 

[richardbrennan]

The problem is you don't know what you've got until the leg is split. I had mine split after 8 years last summer to reveal a badly corroded leg, which was also just eight years old. It was never satisfactorily explained, but necessitated a new leg. From the outside, it appeared fine.

 

[pvb]

The problem is you don't know what you've got until the leg is split. I had mine split after 8 years last summer to reveal a badly corroded leg, which was also just eight years old. It was never satisfactorily explained, but necessitated a new leg. From the outside, it appeared fine.

Hmmm... I'll await the news with trepidation!

 

[Daydream believer]

I used to inspect mine very carefully and could not imagine a catastrophic failure. I would have been happy to continue until forced to change as I have been now.

Do you honestly feel that one can properly inspect a saildrive seal when it is in place? If however, you first removed it for inspection it would seem pointless NOT replacing it at the same time.
How would one describe a catastrophic failure?
A scenario:-
One only needs a bit of weed round a prop to give the drive a good shake to start something off
A small undetected split, following a short motoring trip, then left for 3 weeks,( due, perhaps to an unexpected reason, on a mooring etc) resulting in a leak, causing the automatic pump to flatten batteries, which may be a bit low & not under charge could be quite "catastrophic"
.

 

[RichardS]

They certainly can fail catastrophically as happened to a boat in our previous marina which they charter company only just got to the travel lift in time before it sank. However, that required a serious confrontation with some marine furniture so not a failure in the normal sense of the word.

Richard

 

[peter gibbs]

They certainly can fail catastrophically as happened to a boat in our previous marina which they charter company only just got to the travel lift in time before it sank. However, that required a serious confrontation with some marine furniture so not a failure in the normal sense of the word.

Richard

When you see a cross section of the rubber gaskit it is apparent that catastrophic failure is highly unlikely. Only then if very old and subject to aggressive abuse I'd say. 7 yrs is a realistic minimum for most conditions. 10 is not unrealistic. Pinhole is a possibility but in 23 yrs I've never experienced anything untoward and am now on my 3rd routine gaskit.
The clamping plate will suffer corrosion and need cleaning when changing the gaskit so time for paint to dry is required - not a tide job on the piles.

Always carry replacement seals for the drive shaft. When they go, usually after several seasons, it's time to haul, remove the oil and replace seals. Tout suite. Can happen without warning. Been there.

PWG