Despite being installed less than three years ago, the new engine mountings were rusting badly. They may have been installed unpainted, in the rush to get the re-fitted engine back into Frank before Endeavour (the business doing the refit) closed their doors. The original mountings had been in terrible shape, rotted through and broken in at least one case.
The new port side mountings were rusted worse than the starboard side, so I think that the situation was exacerbated when Frank was hauled out and stood on the hard at St Croix Marine. Tilted just a degree or two down at the stern and to port, sea water in the sump under the engine and in the shaft transmission space was topped-up by rainwater leaking into the sump.
So the port mountings stood in water from June until November, when I returned to St Croix and bailed out the sump.
The mountings are substantial, so will not fail for a good few years yet, but I put some Rustoleum (like Hammerite in the UK) on them. Not a pretty job, but the photos here belie the lack of space and limited access that I had.
Whilst I was at it, I painted the rusty clamp that holds the shaft to the gearbox. If I find the correct term for it, I will edit this!