As soon as the Hysucat is powered the craft is lifted manually from stem to stern, as its foil system prevents it from having to follow the entire contour of each wave. The faster the boat is propelled, the greater the quantity of air it traps within the tunnel between its two hulls providing additional lift. With the hydrofoil design, the more a wave tries to bury itself beneath the bow, the more resistant any trapped cushion air becomes resulting in the forward section of the boat once again being lifted up. Rather than slamming or burying her nose, the boat will ride smoothly from wave crest to wave crest with a stable level running attitude.
The hydrofoils fitted on the Hysucat vessels reduce the effective hull resistance by raising the vessel enough to be lifted out of the water. Effective sea keeping is also improved as is stability. Fuel savings are substantial – up to 30% or more.
Being a twin-hulled craft, Hysucat obviously doesn’t heel in a turn as a monohull would. Therefore, in the case of a twin-engine configuration, the outboards are angled outwards in order to maximize propulsion in a manner that capitalizes on the water being funneled between the hulls as well as the slipstream created by the foils. However the Hysucat will never roll over in turns. On the contrary, it will be a very stable and dry ride the whole way through.
The Hysucat’s advantage comes from the improved lift to drag ratio compared to any planing hull. As well as the reduction of the wetted area of the hull, the foils will also improve the maneuverability of the catamaran. There is no negative behavior of a vessel fitted with foils except that the craft will be more sensitive to trim in flat water conditions. The Once the vessel will get up on the foils at around 15 – 18 knots (depending on the weight), the resistance of the boat will be very small. Thus, the sea ride will be improved and the water friction will be decreased.
The main reason for the lack of Hydrofoils coming into the mainstream is due to the fact that foils are relatively complex to design and install on a vessel. On classic hydrofoil systems that elevate the vessel completely out of the water, propulsion systems need to be specially designed for the foil application, thereby raising the cost and stability issues. For small vessels under 7 metres, the added cost of the hull plus the foil means that the vessel is substantially more expensive to build than a conventional planing hull.
One big misconception related to hydrofoils is that the foil will be damaged or fall off if it strikes something in the water. Unless the strike is substantial, foil systems are able to withstand considerable abuse before being severely affected. However, in the worst case of a high-speed impact with rocks, you will probably lose the hydrofoil instead of ripping off the hulls. The construction around the hydrofoil is specially reinforced, so even if it happens for you to hit something, you will not sink. Rather, you will continue running with the remaining hydrofoil. The foils are made out of stainless steel using US Navy guidelines for impact strength so the foil is probably the strongest part of the boat.
No foreign object will ever get stuck between either of the foils because of the enormous vortex created around the hydrofoil. The air trapped in the tunnel between the foils will not permit anything to get stuck on the hydrofoil.
If you consider the 40% increase in speed; cost savings on smaller engines while keeping top speed; improved sea-keeping in rough conditions, leading to an overall smoother ride; increased payload carrying capacity with little speed loss; faster acceleration, better response when turning on foils; drier ride in choppy seas, less wake at higher speed; 20-40% reduction in fuel consumption; 20-40% increase in cruising range, then the answer is yes!
The hydrofoil consists of a winglike structure mounted on struts below the hull, or across the keels of a catamaran in a variety of boats. As a hydrofoil-equipped watercraft increases in speed, the hydrofoil elements below the hull(s) develop enough lift to raise the hull out of the water, which greatly reduces hull drag. This provides a corresponding increase in speed and fuel efficiency.