Yngmar
Well-Known Member
Correct, there are reinforcement fibres inside (not sure what exactly). I know this because I've cut a sector out of my old one after replacing it (after 15 years). Pretty tough to cut! Kept it as a souvenir. It was absolutely fine, no sign of cracks, splits or tears - couldn't tell it apart from the new one after cleaning it up, but luckily Volvo casts the year of manufacturing into the rubber (else there'd probably be a grey market for used ones)
During my research leading up to that work, I've found ample evidence of them being fine after more than twice the schedule. It's age wouldn't make a difference if it's torn out of the clamping ring due to the saildrive leg running aground as in the link above somewhere (keeping towels handy is a good idea for this scenario as well as a ripped out rudder bearing after a collision).
I'm still glad I did it, because without cutting the old seal into bits I would've had constant doubts nagging in the back of my mind. Also, the thing was crying out for a cleanup and some paint. And the clamping ring had corrosion and needed cleaning up - if that severely corroded and failed, it would cause a leak of medium proportions (it has enough bolts to not fail all around, but a section lifting would let in significant water), so there are reasons other than replacing the rubber ring for removing the saildrive for an overhaul, although probably not as often as 7 years unless you can see serious corrosion from the inside.
