Damai would be 5 star, not 4. All boats have steps to the water, some more than others, but shouldn't be a problem since you aren't really geared up. There a generally stairs to get to you cabin. The metal boats will generally have a shorter walk to the water, e.g. Mermaids, Aggressor, than the Phinisi. The protocol on the Aggressor, formerly Ocean Rover was to gear up and then get in the boat. Another 4-star boat not mentioned is the Seven Seas.
So, Mike, the Gaia website has no names anywhere. Who might the cruise directors be? J&G? or another couple who recently completed their contract?