Generally above 35', you are looking at shaft drives or saildrives.
- Having owned a shaft drive power boat
in the past I hate the constantly wet bilge
but not overly crazy about a permanently submerged sail drive.
Under 35' outboards or outdrives become an option. Both have the advantage that they can be completely pulled out of the water
limiting drag while sailing and corrosion
issues from being constantly in the water
- The Stillete outdrive is the most common if you are dead set on diesel
but with the new 4stroke outboards the fuel
efficency edge is drastically smaller. While mechanically simple, the stillete requires regular maintenance
if you hope for it to be reliable.
- We have a 25hp outboard
in a lowering bucket. Works nice, almost as good on fuel efficency and maintenance
is negligible. Worst case a few grand and we have an entirely new drivetrain in an afternoon.