Bavaria 38 Saildrive.

[John]

Has there ever been a "catastrophic" failure of a sail drive? ie. Has a vessel ever foundered.
Does a normal failure  show by ingress of water through the gaiter? Drama Queen

[dawntreader]

This makes good reading: http://blog.motortechmarine.co.uk/2012/01/16/why-replace-your-ageing-saildrive-diaphragm/

[Symphony]

Sleep easy, but still get it done sometime if you are planning to sell as buyers get nervous and surveyors negative so you could find yourself having to drop a grand to get the sale.

[Spirit of Mary]

This makes good reading: http://blog.motortechmarine.co.uk/2012/01/16/why-replace-your-ageing-saildrive-diaphragm/

This is a commercial article. The last sentences proves this very well.
In the Netherlands a Insurance company is collecting used gaiters with its history for futher analysis by a research center. The goal is to extend the 7 year which now is dictated by Volvo and followed by many Insurance companies. The goal is to extend to at least 10 years.
The corrosion which is showed in the article can arise in less than one year, also within the 7 years, when something is wrong in the electrical isolation of the saildrive. There are examples of fully corroded saidrives(large holes in the housing) in this case. There are almost none examples of leaking or even surface cracked gaiters even after more than 15 years.

Ger