I've never done it, but when I made the rudder for my boat I planned on the eventuality by drilling and tapping a 3/8" hole in the end of the shaft to attach an eyebolt.
Is this the configuration of your boat?
If so, it looks like the shaft tube has plenty of length above the waterline, so that shouldn't be an issue.
The question is if you have access to the top of the shaft, in the drawing above it appears that you do. If so, it should be fairly easy to drill and tap a hole in the shaft (if there's not one already), attach an eyebolt and lower the rudder out with a line run through a pulley temporarily attached to the boom, with a sheet winch
You can probably pull the rudder out and aboard without a diver (with creative use of lines), but to reinstall it, you're gonna need a diver to line the shaft up with the bearings.
If you have a stainless rather than a composite shaft, in the water the rudder may be close to neutral buoyancy (which would be nice), but out of the water I'd guess maybe a 100 lbs., so be prepared to handle that.
Also, if you have a hollow stainless shaft, water must not be allowed to get inside it. I hope you plan on getting a new shaft, if so, accept nothing other than solid shaft, polished and preferably passivated 316L SS or better.