The Harmony 25 hull was designed to operate efficiently at displacement speeds (under about 10 mph). She has a long waterline and relatively modest beam for her length. The underwater shape permits her to slip easily through the water leaving little wake. The cedar strip/ fiberglass sandwich construction is strong, watertight and lightweight. The complete boat, including 390 lbs. of batteries, weighs only 1650 lbs. The modern brushless electric motor works efficiently at a wide range of speeds. These factors combine to give her a remarkable combination of speed and range.
The Harmony 25 is capable of going 20 miles at 6 mph using 80% of the battery capacity. That's more than 3 hours of cruising; slow down to 4.5 mph and the range doubles.