X-302 saildrive diaphragm

[vsb]

One of the winter jobs for my new toy is to change the diaphragms on my yanmar saildrive. The X 302/332 doesn’t use the yanmar rubber outer fairing around the saildrive leg where it exits the hull, but appears to have a rigid plate. The Danish club site suggests you pull it out with an Allen key or similar used as a hook up alongside the leg. This seems unlikely to me: has anybody here done this job on an X yacht?

 

[Moodysailor]

The outer fairing is only there to smooth the water flow over the hull. Sounds like X-Yachts have taken this seriously and done a proper job making a solid one.

No idea how to remove it, but as the S/D diaphragm is a service item it will have been intended to be removed. The worst case would be that it is considered 'sacrificial' by X-Yachts as a racing expense. In that case you could try to remove it carefully, if it fails you could get/make another or use the rubber one supplied by Yanmar.

 

[dunedin]

Are you a member of the X Yachts Owners Association - Welcome - X-Yachts Owners Association

Somebody on there is sure to know. I am aware that X Yachts tend to have fairings around seacock outlets as well as the saildrive, but no idea of the specifics for the latter

 

[Neeves]

You could always send an email to X-Yachts.

Jonathan

 

[savageseadog]

On a Yanmar saildrive there are two diaphrams/seals plus the outer fairing. As there are two seals, and as long as they are inspected regularly, there isn't any need to replace them.

The outer fairing isn't a seal. I'm not convinced that a close fitting Hull exit is a sound idea. More stress on engine mounts.

 

[Skylark]

On a Yanmar saildrive there are two diaphrams/seals plus the outer fairing. As there are two seals, and as long as they are inspected regularly, there isn't any need to replace them.

Interesting comment. Not being provocative nor argumentative but is there any Yanmar-fact in support of your claim?

My understanding is that Yanmar continue to recommend a 5-year replacement. How do you inspect these seals? Against what criteria? Do you remove the outer fairing?

My boat is now 8 years old so it’s a genuine question. Other than check the water sensor once a year I do nothing as there’s no access to inspect anything.

It’s a job that I don’t want to do and I’ve read of no objective reason as to why 5 years is relevant or appropriate.

 

[savageseadog]

The inner seal is clearly visible around the head of the saildrive inside the boat. It's possible to remove the securing band on the inner seal and view the outer seal. The view is limited but you can get some idea of condition.
Regarding risk, how likely is a catastrophic failure? Extremely unlikely in my view. Even if a hole were to develop in the outer seal, the inner seal will prevent ingress. Removing the outer fairing doesn't help in any inspection.

The biggest risk to a saildrive and it's seals comes from a misplaced strop when the boat is hoisted.

Have a word with your Insurance company.

 

[scottie]

The hull rubber is fairing not a seal
Allegedly yanmar shot themselves in the foot when they decried Volvos introduction of sail drives and then had to fit an inner diaphragm and water sensor to deal with the danger that they said existed
fitting a solid flange might be in conflict with the flexible mounts

 

[Neeves]

The hull rubber is fairing not a seal
Allegedly yanmar shot themselves in the foot when they decried Volvos introduction of sail drives and then had to fit an inner diaphragm and water sensor to deal with the danger that they said existed
fitting a solid flange might be in conflict with the flexible mounts

I wonder how many diaphragms have failed, on any Saildrive unit. The replacement schedule sounds a bit like the background to rigging replacement - lacking in any justifiable data for the schedule demanded.

I simply don't recall reading about a diaphragm failure here, not even anecdotally. Reports of rigging failure and mast failure do occur but not frequently.

Jonathan

 

[vsb]

To complete this, the fairing plate was about 3mm grp sheet bonded in by what appears to be epoxy filler and faired in with the same filler. The 2 yanmar diaphragms, which are as far as I know the originals from 2001, absolutely pristine with no damp between them. A sharp chisel was required to shift the plate.

 

[Skylark]

To complete this, the fairing plate was about 3mm grp sheet bonded in by what appears to be epoxy filler and faired in with the same filler. The 2 yanmar diaphragms, which are as far as I know the originals from 2001, absolutely pristine with no damp between them. A sharp chisel was required to shift the plate.

Congratulations on doing this and for reporting back. Out of interest, which gearbox (mine is the SD50)?

I wonder how many diaphragms have failed, on any Saildrive unit……..

I simply don't recall reading about a diaphragm failure……...

Jonathan

All very frustrating. Shortly after buying my current boat I wrote to the Builder to ask them to share life cycle data, specifically, something like a Weibull plot to justify their concern and hence of their 5 year change recommendation. I received quite a patronising response along the lines of “nothing for you to worry about, just contact our Agent when the times comes and they’ll take care of it for you”

 

[Neeves]

As someone who would need to pay - even if I did all the work myself, some of the servicing frequencies advised seem excessively conservative. Rigging and Saildrive seals come to mind. Why a hard raced yacht and a sedately sailed vessel for a retirement couple are subject to the same servicing regime seems questionable. Further, as Skylark says, there seems little to support the frequency of the regime - apart from a money grab.

Our cars are serviced based on distance run and a generous time interval. Not so yachts

I do accept that a yacht bouncing about in a marina will suffer deterioration in its rigging -but to the same extent as a yacht raced hard every weekend .... ?? Why does a Saildirve steal deteriorate whether it is used, or not

I do have to wonder how many yachts are out there with original Saildrive seals from decades ago (how many members here know of seal failures?) how many 30 year old yachts have 30 year old rigging.

I'm not suggesting that we should ignore senility - b ut suppliers do seem to be over cautious.

Jonathan

 

[vsb]

It’s a 2GM20F driving through an SD20. A very good unit I think- the paint on the drive leg is scabby with some areas needing repainting but no corrosion which suggests the anodes are working well: aluminium one on the leg and zinc on the prop.
I shall replace the engine and drive mounts as I suspect them of deteriorating with time, but I don’t think the diaphragms need changing on a 7 year cycle, particularly the double set up with an alarm switch for water ingress between the two layers.

 

[MarlynSpyke]

I wonder how many diaphragms have failed, on any Saildrive unit. The replacement schedule sounds a bit like the background to rigging replacement - lacking in any justifiable data for the schedule demanded.

I simply don't recall reading about a diaphragm failure here, not even anecdotally. Reports of rigging failure and mast failure do occur but not frequently.

Jonathan

The saildrive diaphragm on my Volvo Penta MD2020 unit (on a 2002 Dufour 30 Classic) is now 20 years old. I have been inspecting it carefully every year from inside the boat, which I have owned from new, and at last there are some signs of very fine hairline cracks in the surface of the rubber. So I think the time has come to replace the diaphragm.

I suppose the 7 year replacement cycle stated by V-P is to cover all eventualities, including boats in hot environments. Julanda is kept afloat all year in a Chichester Harbour marina and is sailed along the south coast, so the diaphragm has always been kept cool, in benign conditions for rubber.

I thought it worth reporting this experience of diaphragm life. I too have never heard of a diaphragm actually failing catastrophically.