Norma, without knowing the particulars of the exact piece of property you were inquiring on, odds are there were not sufficient comps that matched your exact search. In lieu of an exact match, other properties may be added as comps that are not exact matches. That detail is not insignificant, especially with waterfront property. You want to make sure that the area of your search offers consistent value regardless of whether the home is waterfront or not. Make sure the entire neighborhood reflects that home you are looking at. You don't want a $500,000 waterfront home backed up by $85,000 pre-fabs!
Good luck on your search.