When you say "wheels" I assume you mean the props. It's not uncommon for cutless bearings to swell up a bit over time and tighten up on the shaft. When we bought our boat neither shaft could be turned by hand inside the boat. They could be turned by pulling on the props but they were still quite stiff. But we had no vibration and no noise underway and we ran the boat this way for some six or seven years.
Eventually we had the shafts out for other reasons and had the cutless bearings replaced as a matter of course. When the bearings were new it was very easy to turn the shafts by hand by grasping the shafts or the shaft couplers. Now, a number of years later, the shafts are stiffer to turn from inside the boat than they were when the bearings were new. If the boat's been sitting for a week or so it takes an effort to "break" them free at which point they turn fairly easily, but not as easily as when the bearings were new.
As the boat you're looking at is out of the water, that can can cause the cutless bearings to "stick" on the shaft as well as make the noise you're hearing. The real test is to see what they're like when the boat is in the water and the bearings are getting the lubrication they need from the water. But I wouldn't automatically assume the cutless bearings are bad just because the shafts are hard to turn by hand, particularly when the boat is out of the water.
Other causes, of course, could be bent shafts, out-of-alignment struts, or the wrong-size bearings.
But I'd put the boat in the water and see what difference that makes, if any. And even if it doesn't make any difference I'd want the opinon of an experienced powertrain person before passing final judgement.
