The 917, 958, 998–any of the 900 units are big, heavy graphs. Based on my experience, the regular 1.5″ Ram ball mount will not be solid enough in rough water to hold the unit tightly in place.Id spend the extra money and get the 111HD unit, with thte 2.25″ ball–Especially for a bow installation, where the impact of rough water is magnified.I made the switch on my boats two years ago, and have never regretted it.Mike Whitten/Germantown, TN