Saildrive seal

[Iain C]

I'm going to buy a boat with a Volvo saildrive. I had a poke around underneath at the weekend between tides, and I noticed that the outermost seal had some gaps around it. Now I'm assuming that this is just some kind of "fairing" seal to perhaps protect the proper seal against mechanical damage, and doesn't actually keep any of the water out, is that right?

It's the lower seal on this parts picture.

The engine was recently serviced (I've seen the bill) and the inner seals found to be in good order and in no need of replacement, but if someone can set my mind at ease I'd appreciate it!

 

[jordanbasset]

It is not unusual and I would not worry about it, happened to my earlier boat

 

[duncan99210]

The outer/lower seal is simply there to fair the hole so there's a smooth water flow across it. It actually has a drain hole or two in it IIRC, so it most definitely not designed to be watertight! The big diaphragm (the donut shaped piece) is what seals the leg to the hull and keeps the water out. Needs replacing every seven years according to Volvo: mine was replaced last year at 16 years old and showed no signs of wear or perishing....

 

[RichardS]

As the seal already has some gaps against the hull it is gradually detaching itself as marine growth and water flow force it off. At some point in the next year or three you will probably find that it has dropped down and is sitting at the bottom of the saildrive leg. It's not a big issue but should ideally be replaced with a new seal next time you haul out.

Richard

 

[Lucky Duck]

I just got in the habit of re-gluing the bits that were coming off while the boat was on the hardstanding.

 

[Quandary]

Anyone got any tips on how to get the old one off, heat, acetone, sharp plane blade?

 

[RichardS]

Anyone got any tips on how to get the old one off, heat, acetone, sharp plane blade?

They usually just pull off .... but use of a hot air gun will certainly help.

Acetone will then probably clean up the residue on the hull.

Richard

 

[Iain C]

OK great, thanks guys.

Out of interest when it's time to change the inner, important seal, how big a job is it? I assume the engine stays in situ...is it a competent DIY job or one left to a professional?

 

[duncan99210]

OK great, thanks guys.

Out of interest when it's time to change the inner, important seal, how big a job is it? I assume the engine stays in situ...is it a competent DIY job or one left to a professional?

It depends somewhat on the boat but most require the engine to be moved forward to allow the Saildrive to be lifted out. The diaphragm is sandwiched between the upper and lower parts of the Saildrive, so you have to take the drive out to spilt it and replace the diaphragm. Technically, not a difficult job and when you buy the diaphragm kit, it comes with a pretty comprehensive set of instructions on how to do the job. Take you a day or so with a mate to help in the grunt work of moving the engine and Saildrive.
However, I paid a chap to do the job on grounds that I could do without yet another bad back!

 

[Gin]

I once made enquiries of my insurer when looking at a boat with such a seal and was told that in the event of a flood/sinking claim attributable to a failed seal they would want to see proof that the seal had been replaced within the previous 7 years.

 

[johnalison]

I left my last seal for ten years, fully confident that it would not let me down, and even if so, not catastrophically. When it was removed it was said to be as good as new. I don't want to be recorded as recommending this, but you would be very unlucky to have a failure, especially with recreational rather than charter use.

My outer fairing has often shown some looseness at the end of a season, which does worry me a little because a friend with a new Hanse had one come loose in his first season. The flap interfered with the Kiwi prop and needed a haul-out somewhere abroad.

 

[spannerman]

Having done this job on various different sailboats, I have found the easiest way is to remove the prop shaft from the saildrive as this lets you lift it vertically or at whatever angle works depending on the structure at the rear of the engine room. If the shaft is in then you have to tilt the leg backwards as it goes through the hull to clear the shaft. If you have good access then its not a problem but some boats require a bit of dismantling of bulkheads to get the drive out.

 

[Tranona]

Having done this job on various different sailboats, I have found the easiest way is to remove the prop shaft from the saildrive as this lets you lift it vertically or at whatever angle works depending on the structure at the rear of the engine room. If the shaft is in then you have to tilt the leg backwards as it goes through the hull to clear the shaft. If you have good access then its not a problem but some boats require a bit of dismantling of bulkheads to get the drive out.

That is good advice and what the dealer did when he changed the drive on my old boat. Also provides an opportunity to replace the seals in the lower housing which is easier when it is out.

 

[Poecheng]

I changed insurers this summer to an oft-recommended (on the forum) insurer. Sent them the survey from 2014 and an update of what recommendations had been attended to.
Stated I had not replaced this part (which I believe original from 2005) and that I didn't believe it was necessary (having read threads such as this) and they didn't require anything to be done in that regard.

[They just wanted a gas safety certificate within 12m of taking out the insurance - furry nuff ]