The scissors jack worked fine and I didn't put a hole in the bottom of the boat.
I wasn't too worried about the oil
pan as the W46 is based on a small automotive diesel
and, in 40+ years in the auto service
industry, I don't recall
an engine that couldn't safely sit on its pan. Leaking from compressing the gasket
shouldn't be an issue as the clamping forces of the pan bolts is a lot greater than the weight of the engine.
I couldn't do 1 corner at a time as the top mount studs are too long and I don't have the tools on board to remove the mounting brackets on the block.
I put the jack under the transmission
on the back end to get better leverage and not lift
the entire unit.
The hardest part was getting onto the nuts in the mounting beams for the aft mounts.
The R&D mounts appear to be well made and should last longer than the old ones. I expect the engine to stay put now and hopefully be a little quieter.
Now I just have to align it.