The Bull Dog has more volume in all the places you want it. comes with a fuller wider nose and more thickness in the tail. The double wing swallow brings in the tail block from the wider outline making for a tighter tail block. A semi down rail that still allows you sink the rail even with more volume. Slight double to vee off the tail. Medium low nose rocker and low tail rocker. Flat deck. Rides best as a tri fin or quad. Only comes as a double wing swallow.