Saildrive diaphragm durability in mild climas

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Chanquete

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Buenos Aires, Argentina
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We all know that Volvo for example recommends its change after 7 years.
I infere that its durability is influenced by external condiciones: salt or fresh water, extreme winters or mild climas, water contaminación, etc.
I would like to know about práctical experience of any diaphragm environmental durability dependence.
Thank in advance
Chanquete
 
I've changed mine twice in 13 years, and coming up for anouther in a couple more.
I don't think the type/temp of water would effect it to any degree. Oil/deisel mixed in with some dust/dirt to create a grinding paste gooe would be the only nasty and on both of my replacements, even with the gooe present deep in the crevasse, there was no sign of any deteriation, if cleaned and put beside new one apart from the age stamp it would be hard to tell them apart, don't know if that helps.
I think I read on here some years back, there's been know reported failures.
P
 
Apart from the diaphram being damaged by physical tearing in situ - and I only know of one case of that - every report I have read says that removed diaphrams have appeared to be in perfect condition.

I keep a close eye on the condition of my Yanmar upper ones and they look perfect to me after 8 years so I'll not replace them unless the lower one ruptures and triggers the water ingress alarm or unless I need to remove an engine for other reasons.

Richard
 
I replaced ours last winter.

It had never been replaced from when the boat was first built in in 2002.

It was difficult to detect any difference in the condition or pliability between the 14 year old old one and its replacement.

Nb the old one was date stamped 3 years before the boat was built suggesting that either the sail drive or the gasket had been in the stores for a while before new installation.

Our boat has always had a dry and clean engine bay with no hot water , oil or fuel leaks.

The only other potential source of degradation will be UV light which is unlikely to be an issue at our lattitude, muddy waters and position of the sail drive!
 
TSB240 said:
I replaced ours last winter.

It had never been replaced from when the boat was first built in in 2002.

It was difficult to detect any difference in the condition or pliability between the 14 year old old one and its replacement.

Nb the old one was date stamped 3 years before the boat was built suggesting that either the sail drive or the gasket had been in the stores for a while before new installation.

Our boat has always had a dry and clean engine bay with no hot water , oil or fuel leaks.

The only other potential source of degradation will be UV light which is unlikely to be an issue at our lattitude, muddy waters and position of the sail drive!
Click to expand...
 
I changed mine at 6 years. The used diaphragms and seals were good as new. I have never heard of any sinking or near sinking caused by diaphragm failure. IMHO the recommendation for change before 10 years is an exerecise in generating spares revenue for the manufacturer.
The cost of parts, labour, craneage, adhesives, touch up paint etc will mean a cost of around £1500 for most people to change their diaphragms. If they have a 5 year life (i.e. Yanmar) then the cost averages 1500/5 = £300 per year or £6 per week. I think manufacturers using sail drives should be required to post a warning "this saildrive will cost you £6 per week in maintenance costs" - and that is without oil and anode changes
 
TSB240 said:
I replaced ours last winter.

It had never been replaced from when the boat was first built in in 2002.

It was difficult to detect any difference in the condition or pliability between the 14 year old old one and its replacement.

Nb the old one was date stamped 3 years before the boat was built suggesting that either the sail drive or the gasket had been in the stores for a while before new installation.

Our boat has always had a dry and clean engine bay with no hot water , oil or fuel leaks.

The only other potential source of degradation will be UV light which is unlikely to be an issue at our lattitude, muddy waters and position of the sail drive!
Click to expand...

Same experience, changed mine after 15 years. No signs of wear or decay. I've cut a sector out of the old one as a souvenir. Will not be the slightest bit nervous in another 15 years. The only way these could be damaged is by something sharp poking them. Mine had oil and saltwater on the inside, which meant the metal ring needed cleanup and painting, but the rubber was not bothered by any of it. Suspect the metal ring is the real reason for the replacement schedule - that could corrode and give eventually if left in a wet, salty bilge.
 
TSB240 said:
It had never been replaced from when the boat was first built in in 2002.

It was difficult to detect any difference in the condition or pliability between the 14 year old old one and its replacement.
Click to expand...

That's reassuring.

Mine is 18 years old at present and I was thinking of doing it shortly but if I leave it for a couple more years the next one should last me til I'm 75.

I will give it an autopsy when it comes out and report my findings.

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