Re failure modes of SD sails
As already mentioned on another thread we had a failure back in 2011 on a Yanmar
SD20 due to brute force.
We sailed at full speed into a huge pile of disposed fishing
net, which stopped us within a second. The pile of net was the size of a house, and floating just under the surface.
It was visible by the old dirt marks around the SD that it had moved a few mm and we took very small amounts of water
. Just enough to trigger the bilgepump every few hours.
After liftout it became clear that the seal was still OK, but the fibreglass around the bolts was cracked and water
was creeping in through these cracks.
This happened just weeks after we replaced these seals
, no clue if the old ones (although looking as new) would have survived as well.
This happened on our Lagoon
410, which had the engines under the bed
and no watertight bulkhead. That -in combination with crossing the atlantic- was the reason to replace the seals
I don't know about the FP Orana
but if its like our FP Mahe with watertight bulkheads glassed into place and no penetrations below bridgedeck level I would not change the seals without good reason.
there are better ways to spend the money
to improve safety