Diaphragm replacement

[PhilB]

I am contemplating replacing the saildrive diaphragm on our Bav 36 - Volvo 2030 - as its now over 7 years old and should anything untoward happen I can see the insurance company backing away since this is "standard maintenance"...
Has anyone tackled this themselves as it looks fairly simple to move engine forward and drop saildrive ?
Any special tools or spares (other than the expensive kit) ?

[Symphony]

Have not done it myself, but watched the Volvo fitters do it (on a B37). The engine moved forward and the drive comes out through the top. They took the bearing housing off the bottom and pulled the shaft out to make it easier to go through the hole in the hull. Re-installation is the reverse. Two fitters changed the whole drive starting at 9.30 in the morning and having it running by 4 in the afternoon. Typical timespan for a DIY is taking it out one day, in the workshop to change the diaphragm and back in the next.

[Nigel]

It took two of us a day. It would have been quicker if we hadn't tried to do it without moving the engine by the specified distance.

[PhilB]

Thanks for rapid replies - I have requested a quote from Agent so we'll see how much I can save doing it myself !
Are there any sites that have a step by step guide - I saw a YouTube vid that helped ?

[Symphony]

Should be around £800. 10 hours labour plus the parts which come with consumables at around £250.   Labour rates are around £50 hour without travelling time in our area ( Dorset). So DIY saving around £500.

[Rampage]

IIRC PBO did an article about it a bit ago and it is available as a download showing how it's done.

[Cat2]

Did mine last year (2020) turned out to be a non event. a few days before I soaked all the nuts and bolts with plus gas to be sure that there would be no problems with seizes bolts etc.
As it turned out all the N & B came undone without a problem.
Used a simple engine lifting block and tackle suspended from a timber across the top of the companion way to take the weight of the engine as it came forward. ( remember to support the saildrive from below as well as under the gearbox and remember it  may wiggle about a bit when separated from the engine.
Only unforeseen issue with me was that those  clever (?) people in the  factory  had fitted a bulkhead to the rear of the gearbox, post engine installation, which prevented us rotating the gearbox / saildrive through 90 degrees aft.
Had to cut a bit out of the  bulkhead ( Bav 32) to allow this, but well worth it as it gave stacks of room to work.
Also turned out to be a good idea to have moved the table.
AND remember when you are  doing this it's difficult to access the boat through the companion way.
Remember to leave the fore  hatch open ( and remove  cushions etc).
For the record, the old one was in pristine condition !!

[Moodymike]

Did you leave the engine suspended or rest in on the mountings?  Was it easy to cut the bulkhead?   Mike. B32

[Cat2]

Mike.
Moved the engine much further forward than the  minimum suggested; basically sat it on some carpet and parked it in front of the  toilet door. this way you get easy access to remove / refit the  assembly.
As for the  bulkhead cut out ; cut / remove the  cross member at the  front of the  aft berth then cut a rectangle about 12 inches high and the width of the cut out  cross member using a drill for the  corners and a jig saw.
Retained the  cut  out and expanded the  edges with some mahogany trim; screwed back in place.
Found it easier to fit a new piece of timber to make a new cross member which fitted on to the  stumps and the berth top.
Took the  saildrive / gearbox home to spit them apart in a garage ( much warmer etc) .
PM me if you need any more info.
Bill

[Moodymike]

Thanks for the info, certainly take you up on the offer of more advice.

[Bob Baynton]

I'm very curious how many owners have replace the diaphragm in their boat that is more than 7 years old. My Bav 36 is 2003 vintage and I am contemplating replacement but wonder what the chances are that the diaphragm really needs replacement. Of course, there is the insurance issue, I suppose.
It would be interesting to take a poll how many have and haven't done the replacement.

[Odysseus]

I agree with the comments so far and have changed mine on my last boat, a Scanmar with a 120S leg, it was 17 years old and when I took it out I could not see any deterioration on it, so took it to work (I made nitrial products) and had it looked at in the Lab. Their verdict, there was no sign of deterioration, apart from sea creature and bolt scaring.

The above is not a recommendation as when to change the diaphragm, but I would like to know what the specific grounds for recommending people to change it was. (apart from the obvious one) I expect it is a set of hypothetical conditions or poor manufacturing possibilities that no general sailor would ever see.

But you have to be careful with your insurances.

Odysseus

[PhilB]

Thanks for all replies - boat coming out next week to replace diaphragm and antifoul - cost was £725 inc parts and oil, seals and anode,lift in and out so I'll let them get on with it. Would be interesting to get a view from an insurance expert as this is clearly a maintenance item and was pointed out on my survey before purchasing. Looks like they last a lot longer than 7 years but I'm sure if you had a major insurance claim then items like this would provide a nice escape route for them...

[Bob Baynton]

Have any Bavaria boat owners actually experienced failure of the diaphragm and if so, the age of diaphragm? Anyone replaced the diaphragm and determined that the diaphragm was in poor condition and if so, the age of diaphragm? Thanks!

[njsail]

Here is my take on the sail drive diaphragm (aka gasket).  I replaced mine last spring after 10 years.  Yes the manual says replace every 7 or so but I left it until 10.  I took pictures of the old one for those who were curious what a 10 year diaphragm looked like.  I know I wondered myself.  The gasket was in great condition.  There was a slight wear on the outside / water side.  note that I don?t have an external boot.   I leave it open and take out any growth when I haul for winter.  I still feel it was the right choice to replace.  I sleep better.  A failure of the saildrive diaphragm would be catastrophic which is why it's such a heavy duty high quality gasket.  I've heard of gaskets not being replaced for 15 years and it still was in great shape.  My thought is why chance it if you don't need to.  Good luck with your project.   

[Odysseus]

I have found Utube to Nealy always have a good video to watch and they have a few on this subject, just put

"volvo saildrive seal replacement"

in and like magic lots to view.

Some are better than others but there are a good selection there.
MR STONE is a very good one


Odysseus

[Bav32]

Hi guys,
Just took my saildrive of the boat. There was not room enough to take it in one piece so I disconnected the upper and lower part when the saildrive was still attached to the boat. Now comes the tricky part. How do I install it again without breaking it or breaking my back? Is there any issues with installing it in the same way I took it of?

[Rampage]

The hole through which the Saildrive goes should be large enough to fit the Saildrive through in one piece. However, you need to remove the propeller and the shaft to make the lower part of the drive small enough to fit. Trying to reassemble the drive I place will be difficult and may lead to a nipped gasket.

[Salty]

Have any Bavaria boat owners actually experienced failure of the diaphragm and if so, the age of diaphragm? Anyone replaced the diaphragm and determined that the diaphragm was in poor condition and if so, the age of diaphragm? Thanks!

This is a very good question from Bob, and considering that it was asked way back in 2012, the thundering zero response very clearly points either to the remarkable longevity of the sail drive hull seal, or that we all gave in to our worst fears and changed it out because Volvo said thats what we ought to do, but without any substantive evidence on which to base their recommendation. On the basis of zero replies to Bobs question, the recommendation from Volvo to change it after seven years of use must surely be overly conservative.

A friend of mine has a Dufour 41 where the sail drive seal remains as installed from 2001, so its now 20 years old, and currently he has no intention of taking it out to check its condition. I had the seal changed on my B36(2002) when it was 9 years old. This was on the basis of being a newbie to sail drives, and concerned that it should not fail within the next few years. Whilst reassuring that it was in good condition, what an absolute waste of good money that was !

Has anyone ever removed a seal and cut through it to check its condition, and if so how old was the seal when it was removed, and what were your findings regarding both its condition, and its constructional capabilities. Also does anyone know if one of these seals has actually been tested to destruction, and if so what was the opinion of the testers at that time, or did they give up on trying to find out when it would likely breakdown ?
Maybe this is a question that we should put to the yachting press, and/or to Volvo themselves ?

[Lazy Pelican]

Our's is coming up for 16 years old and I've no intention of replacing it in the foreseeable future.
As far as I'm aware there are no recorded cases of the Diaphragm failing catastrophically, despite millions being in use.

[Bav32]

I have now mine removed. It looks perfectly fine on top, but underneath it has small cracks. They are not deep, but if I would have seen those I would have changed the diaphragm at once. I will cut the rubber to check it at some point when I have time. I'll get back to you with pictures when I do that. Mine is from 2003, but from a boat from 2004.

[tiger79]

Our's is coming up for 16 years old and I've no intention of replacing it in the foreseeable future.
As far as I'm aware there are no recorded cases of the Diaphragm failing catastrophically, despite millions being in use.

This sort of discussion crops up from time to time.  The diaphragm is certainly a meaty piece of rubber, and it's difficult to find evidence of failures.  But the elephant in the room is the insurance company.  If your yacht were to sink for any reason, the first thing your insurer would do would be to look for ways of rejecting your claim.  It's likely that this would include a question like "have you replaced the saildrive diaphragm at the recommended intervals?", probably with a request to see the receipts.  The problem is Volvo Penta's recommendation on replacement intervals.

[symphony2]

But that would only happen IF the cause of sinking was failure of the diaphragm. Sinking from any cause is extremely rare and from this cause seemingly vanishingly rare.

[primozk]

Hi everyone,
I'm a newcomer to this forum and owner of an Bav34 year 2000 with a MD2030 and a 3 cabin version which I bought a year ago. I'm reusing this post as also my question relates to the diaphragm replacement.

I realized the previous owner did not change the diaphragm at all. So when I read about aging - this one has now 22 years (OMG) and got a small leak now - small drops coming trough the membrane. There is some water around the diaphragm and I got maybe max half a liter into the engine room after 15 hours under engine. I assume the diaphragm is somewhere at the water level otherwise I'd be already under water (??). I can assume the diaphragm could been damaged last year when repairing the saildrive.

There is no doubt to replace it asap. Speaking to my mechanic he says he needs to dismantle also the cabin to get the saildrive out  - claiming a huge work to be done. Any experience from the Bav34 / 2000 owners how the saildrive change is done? Looking some youtube videos on the topic seems on the other boats was some room to lift the saildrive out.

Many thanks,
Primoz

[Yngmar]

primozk, if the seal itself is actually leaking, it's high time for a swift haulout. The seal is well below the waterline, nearly at the lowest point of the hull. I kinda doubt the seal itself leaks, it may be the ring or the seacock or something else, but you can confirm by wiping it dry and observing where water droplets first appear.

I don't know your boat, but a professional saying they need to dismantle the cabin to get something out often translates to "it's easier for me to do demolish your boat a little than to work in this awkward space and do it the hard but less destructive way". Have a look yourself! The job means disconnecting engine from saildrive, supporting engine and moving it forwards about 5cm or so. Then the saildrive lifts out upwards until the leg (with propeller and optionally shaft removed) can be angled out of the hole. You'll see how much clearance that takes and if it's there or not. It probably is, because Bavaria did think of this when designing the boat, at least on the models I've seen.