The new 1550 is a couple inches longer and wider. The gunnels are shaped a little differently and apparently keep sea spray out a little better. The 1550 has a much bigger front pass through window. Unfortunately though the biggest thing and the downfall IMHO is that the new 1550 doesn't have a self bailing hull. This model has scuppers so can take serious water without you wondering if the Bilge will keep up.