If you are replacing the saildrive only check the gear ratio of the new unit.
Yes, that`s an important point. My SD110S has a ratio of 1.66:1, what was originally designed for engine RPMs at about 2500.
The Kubota is running at max 3600 w/ 14,9KW, but I managed it in the way that the prop is designed for engine revs of 3000 RPM. At that RPM, the Engine still has 12,4 KW, what is fairly enough for my small boat. According to that, I use a 14x6x2LH Volvo-Penta folding Prop. Works good.