The Wow!10too hydrofoils are fixed in position, but can be slid out for transportation. They curve upward and outward from the boat’s bottom. The attack angle is +6º. To adjust the attack angle the skipper moves his/her body forward or aft. To increase the foil’s depth of immersion the skipper moves to leeward. When sailed flat, the edge of the hydrofoil where the hydrofoil enters the hull is just below water level. The gunwales, forward and aft of the hydrofoil, consist of buoyant volumes which provide anti-heeling assistance by increasing the lever arm of the hiking force. They are removable. The beam at the waterline is narrow to reduce form drag. The bottom is almost flat to enhance planing. Sail standard area is 119 square feet (11 sq meters). Options for sail areas of 53, 75 and 96 square feet are also be available as are alternative foils for kids and speed sailing. The hull weight is approximately 45 lbs. The hydrofoil decreases the apparent weight of the boat, reducing skin friction and form drags. The boat is about 10 feet long. The leeward hydrofoil increases the hiking lever arm when heeling.
An alternative rig is also possible which uses the mast from an 11 rig with a raised boom and the sail from a 9 rig. In this situation the boat can be sailed standing up, combining the features of a windsurfer and a dinghy.
The image above shows rig 9. The image to the left illustrates the operation of anti-heeling features of the boat. It can be seen that the lever arm of the hiking moment increases sharply to leeward as the hydrofoil immerses, and as the aft and fore gunwale cavities engage the water. The hydrofoil causes the amount of anti-heeling lifting force to increase as boat speed increases. The angle of heel depends on the hiking position of the skipper.
The image to the left illustrates the operation at various heel angles. Note that the hydrofoil produces the most lift at the high heel angles consistent with increases speed, and the hydrofoil acts as a combination lifting foil and planing board. Because the boat is lifted, the hull exhibits little skin friction or form drag. Note the lengths of the foil normally used for various sail rigs. The dotted lines outline the buoyant gunwales.