High performance results from a combination of two main factors: providing the boat with enough power and reducing her resistance in order to utilize this power in the most efficient way. Some designers focus performance optimization on the power increase. SpeedDream100 is all about maximizing efficiency.
SLENDER HULL THAT SAILS THROUGH WAVES
High performance results from a combination of two main factors: providing the boat with enough power and reducing her resistance in order to utilize this power in the most efficient way. Some designers focus performance optimization on the power increase. Multihulls are typical of this approach as they grow larger and wider with every new generation to achieve higher and higher sail-carrying capacity. The problem, however, is that over-powered vessels are over-stressed, requiring more and more robust structure to survive. This comes at the expense of extra weight, calling in turn for even more power to maintain speed.
Our solution is to reduce drag by all means possible. This way all available wind power is used more efficiently, requiring less sail area to achieve higher speeds. Less righting moment is needed, the boat is less stressed and can in fact become lighter while remaining just as strong. Lighter means faster.
To greatly reduce resistance SpeedDream features a relatively narrow, slender hull, almost triangular in plan view and equipped with a sharp wave-piercing bow. The goal is to reduce drag in heavy seas as well as to minimize pitching and slamming.
The boat is designed to sail most of time with a constant heel angle of around 20-25 degrees. This angle of heel is maintained by adjusting sail area and keel angle to suit wind conditions. Both the hull and rig are optimized to be at peak efficiency in these conditions with the hull having two narrow, planing surfaces port and starboard, each tilted at 20-25 degrees.
During further design development we will have to verify the optimal heel angle and determine both shape and width of the planing surfaces to achieve best combination of maximum hydrodynamic lift and minimal hull drag. The overall hull design will concentrate on reducing its volume and surface area, while moving buoyancy and hydraulic lift as far outboard as possible.
THE ULTIMATE CANTING KEEL
The VOR 70 rules limit keel cant to 40 degrees. Geometry of currently used canting systems allows maximum cant up to 50 degrees, beyond which loads grow dangerously high. For the SpeedDream concept we have developed a proprietary system that allows much higher cant angles while maintaining significantly reduced loads. The goal is to ultimately taking the keel completely out of water and thus removing significant portion of the strut and bulb drag, eliminating their buoyancy and maximizing righting moment.
Even if the keel is going to periodically get submerged in waves, on the average this concept promises sizable benefits for overall drag reduction. Future research and development should concentrate on finding optimal keel and strut shape to minimize drag while awash with waves.
A BOAT WITH WINGS
Wings were attached to the keel in 1983 to help the Australians win the Americaís Cup. Hydrofoils allow a tiny Moth dinghy to reach speeds of 30 knots. Recently we saw a huge wing sail propelling BMW Oracle in their Americas Cup victory. Now the SpeedDream designers are looking closer at wings, trying to utilize uniquely shaped hydrofoils to create additional righting moment and to partially offset the boatís displacement. Placed near the center of gravity to diminish the negative effect of hull movement on their performance, these foils will be capable of creating lift equal to 30-50% of the total displacement. The wings could be retractable or fixed and could be used as separate appendages or in combination with a daggerboard. The parameters of the wing will be decided in the later stages of design process.
MAKING A WET BOAT LESS WET - AND MORE BEAUTIFUL
Itís hard to underestimate the importance of the deck design and layout as it relates to performance the SpeedDream boat since at high speed her deck will frequently get submerged. Its shape will be sculptured to quickly shed water and to prevent large amounts of water reaching the cockpit. All of this will help reduce resistance and provide the best protection for the crew.
Naturally the task of protecting the crew from the elements on a boat intended to reach 50+ knots in real ocean condition is an enormous design challenge, but we have a few interesting tricks up our sleeve that will help make this inevitably wet boat, a little bit less wet and more comfortable for her crew.
The deck, with several strategically placed breakwaters, is designed to shed water aside as quickly as possible. The cockpit is set as far aft as possible and is significantly elevated relative to the rest of boat. Both the helmsman and crew are protected by oversized dodgers. The cockpit sole is a mesh trampoline with a deep, steeply sloped channel below that allows water to easily discharge through the open transom with minimal impact on the crew and boat speed.
All the functional attributes of the SpeedDream design also contribute to the boatís strikingly futuristic image. The SpeedDream design team views design as part science and part art and believe that beautiful boats are fast boats. This boat looks like nothing ever seen before and to our eye she is very beautiful. Therefore she has to be very fast.
LEARNING FROM POWERBOATS
Among other venues we are actively exploring are applications of stepped hulls, spray rails and other speed-enhancing features widely used on powerboats. The next step will be to take a closer look at the benefits of bottom aeration in order to further reduce wetted surface. And thatís only a start. During the extensive research and development process, throughout design, construction and boat testing, designers and engineers will keep improving our revolutionary SpeedDream concept until it evolves into the most extraordinary speed machine ever.
A SYMBIOSIS OF MAN AND MACHINE
In addition to a wide use of the most advanced design and engineering software (CFD, VPP and FEA), as well as accurate weather analysis and prediction, a unique package of the SpeedDream proprietary software will be developed in cooperation with the leading software developers and research centers. It will allow precise control of the canting keel, rig and winches, and to some degree sail trim.
It will also help minimize the energy consumption necessary to operate the boatís controls. Numerous stress sensors connected to a central CPU will be installed in crucial points on the hull and rig structure to monitor loads and to alert the crew in case they are reaching a safety threshold. By measuring the actual loads and stresses that the boat is under, instead of using the arbitrary design safety factors, will result in considerable weigh savings while making the entire structure lighter and more durable.
Our goal is make SpeedDream a true 21st century technological marvel, a symbiosis of man and machine, which fully integrates the sailorís experience, skill, intuition and sensory reactions with the computerís power and speed.
RELATED PAGES * SD100 Design Background * Record Setting * Why a Monohull? * Back to SD100