Good questions. I was unable to really test it under sail alone as there were light winds that weekend. I did sail it for approx 10 min under sail alone, but was only making about 4 knts in light air. Not a real good test, IMO, on such a stout boat. It didn't seem to pull to the right. I was on a port tack, but didn't have any appreciable weather helm to port either.
The diver checked the blades for movement, and said that they seemed to be all at the same pitch.
well, water might not be clear enough, but he could have read the pitch to be sure...
Edit, your diver can push and pull all he/she wants, it's not diddly compared to the force applied when the boat is moving...
I meant pull to starboard when drifting / in neutral. Next time you get the chance in your sunny clime just push her up to speed, put it in neutral and see if it still pulls.
if it does, it's drive train related - might be a loose cutless bearing even, more likely prop related.
If it doesn't, your diver is blind and missed the crab pot hanging off your keel.