Don’t expect to discover any relief from this yacht’s intimidating presence when you peer below the waterline. Her fine U-shape sections forward transition to a relatively shallow arc bottom aft, which meets the topsides in a sharp chine of the type you’ll find on a Volvo 70 racing yacht, for example. Although naval architects disagree about the benefits of chine hulls, most accept that a well-designed example planes more easily, and stays on plane for a longer period of time, than does a hull with rounded bilges; i.e. no chine. The consensus among designers also states that the chine should be kept out of the water when the boat heels to a breeze.
Chine-hull yachts also have to be light enough to plane, and at a displacement of 66,000 pounds, this one is. Infiniti predicts that the 100 will sail at 20 knots, or faster, on a reach, which equals a speed/length ratio of nearly 2.00, instead of the more common 1.34. An increase in wetted surface area and the subsequent reduction in light-air performance are the compromises this type of hull demands, but that’s a small price to pay for an exhilerating top speed.
A ballast bulb, shaped like a super-streamline torpedo, hangs from the tip of a deep, high-aspect fin keel. An equally high-aspect rudder steers the yacht. The high lift-to-drag ratio of each appendage fits the boat’s potential for high speeds, but they may stall easily at the low speeds achieved when she sails in light air. The helmsman will have to be attentive.
So far we see nothing new here, I admit, but the yacht has a third foil — this one dedicated to reducing heel and pitch and damping motion, which can be uncomfortable when the yacht sails upwind in heavy seas. Developed by Welbourn’s Dynamic Stability Systems (www.dynamicstabilitysystems.com), this foil lives athwartships in a slot molded into the boat’s bottom. Its location and thickness keep it from intruding on the accommodations. The foil deploys to leeward, and its hydrodynamic shape counteracts the heeling force of the sails. The effect is similar to that of water ballast or a canting keel, but without the complicated engineering. On a cruising boat, the crew and guests may appreciate the foil’s ability to reduce pitch and roll as much or more than the reduction in heeling angle.
Aboard relatively small yachts, the crew operates a single foil via line and tackle. Aboard large yachts, a hydraulic mechanism deploys and retrieves a separate foil on each side. Fully deployed, the foil extends about the same distance outboard of the yacht’s bottom, as does a canting keel.
Welbourn’s testing has proved the effectiveness of Dynamic Stability Systems and its ease of operation aboard a small boat, and I have no reason to believe that it won’t function perfectly aboard the Infiniti 100 S. If you want to amaze your sailing buddies and dominate the talk at the yacht club bar, you couldn’t find a more compelling design to build. I can’t wait to sail her.
Draft: 14’9”(lifting keel option under consideration)
Displ.: 66,000 lb.
Yachtzoo, +377-9770-5200, 954-767-1035; www.yacht-zoo.com