In general you'll find that several bits of info for changing out a cutlass without pulling the shaft. Its doable but it takes the right tools.
Doing it in the water adds a whole other level of difficulty and potential problems to it.
First you have to find a diver that is willing to do it and has the tools and knowledge to go with the willingness. That guy is probably going to cost you at least $100 an hour, probably more. In San Diego a diver charges $150 to take off a MaxProp and $150 to put it back on. I know cutlass bearings and MaxProps aren't exactly apples to apples (but your prop will have to comeo ffto change out the bearing) but its something that takes willingness, knowledge, and the right tools. Not every diver has all three.
Might end up being best to leave it for a haulout. But for sure call up the dive services in your area and see what they have to say.
A diver should be able to do it. However, if you feel comfortable doing the job yourself, it may be cheaper (or pretty close to a wash) just to haul the boat, change the cutlass yourself (and inspect the rest of the boat's underwater bits), and launch the next day to avoid lay days.
I changed my own cutless bearing on the hard a few years ago. Boy, what a PITA job that was on land. It took hours of labor. I can't imagine trying to do it in the water. Power tools don't work well under water!!!
I won't say that it can't be done in the water but you and I just can't afford to pay what it might cost to replace a $50 part.
Much, much, much easier to do on dry land without having to worry about the boat possibly sinking.
I wouldn't even ask a diver IF they would do it.
Now that I think about it for a minute, I suppose it depends on whether your boat has a fin keel and the cutlass is in a separate strut, or your boat has a full keel and the cutlass is inside the trailing edge of the keel. In the case of the latter it might be way too difficult for a diver to get the old bearing out. But, in the case of the former a competent diver should be able to do the job (assuming that the shaft is fairly well aligned). Although, as I said above, it might cost less just to haul the boat and do the job on the hard (and hauling the boat gives you a chance to look over all the underwater bits too).
Came across this post and thought as a professional diving company we should set the record straight. Here in San Diego, BlueTech Marines technical diving team can replace the cutlass bearing on a shaft up to 2” diameter for much cheaper then a trip to the yard.
Normal process involves pulling the prop and removing the shaft to get the bearing out. That adds up quickly in labor, parts and a haul out fee.
Our team can do this job in water without the need for Driveshaft removal or haul out. We use state of the art specialized press to remove the bearing and press in a new one in under 2 hours.