Hi David,
1. Bud Taplin's approach is fine, I personally prefer a plug with a flange that has a hole for a slide hammer to pull the cutlass bearing out. I do not like butchering the CB with a screw driver out. I do some of these things in my machine shop (I design and build molds for the investment casting industry primarily) and the slidehammer is a threaded rod and nuts with a block as the hammer. This might work also underwater with some leakage that obviously has to be dealt with.
2. Make sure that the shelf above the shaft log is easily removable. I am sure that the Yanmar is positioned perfectly to match up with the driveshaft flange. Something always shifts, and then the cutlass bearing wears, and the shaft seal leaks. That's when you want to be able to get to the leak in a hurry. I had the same idea, but the US Westsail 32s have a ledge underneath the lazarette that's where some tools are stored, and I sit on the shelf when working on the engine..
3. I do not know what your back ground is, but I don't like propeller shaft misalignment. I had to switch engines in Nawiliwili, Kauai,Hawaii. I did it all by myself. The docks are fixed concrete there, and I built a dolly to push the (one year)old VolvoMD3B engine from there into the parking lot. I made a pattern for a universal engine mount and took the whole thing back to the mainland. In Olympia, Washington (that is also were Michael Abrain lives) I purchased a different engine and made a "universal engine mount" that fits onto the W32 Perkins 4-104 bed. My next engine is a Faryman 2banger that was popular with the US Coast Guard. The engine is not aligned with the propshaft. The propshaft sits axially fixed with a multi u-joint and telescoping connection to the engine. I have a 3-4 degree misalignment which does not matter. It worked well for a couple years until I hauled Polaris to modify her some more.- Again I do like my dry bilge, & there is a very long sequel to my story.
Fair winds, G-d speed.
Mike Zorn
Westsail32 Polaris