My Uncle has taken a tour out of Homer Alaska a few times. They run Bear tours. I think it is this company.
I do not know of any ship tour, but this does not mean that there isn't one.
My Uncle loves this tour and plans on doing it a few more times.
Not sure if the above link will met TOL of cruise chat. However if you Google "cruise ship tour to see bear in alaska" you will come up with some information.
Hope this helps