Cummins Marine teams with Sea Sport Boats and John C. Kiley on New Concept Catamaran
Sea Sport Boats of Bellingham, Washington have been building fibreglass planing hulls since the 1950s. Cummins has been building diesel engines since 1919. Designer John Kiley's resume includes over a decade with the famous Boston-based deep-V hull design firm of C. Raymond Hunt. Now the three have teamed up to take the joy of moving a hull across water a significant step further.
For the past several years, Massachusetts-based Kiley has been perfecting a uniquely American catamaran design that shows elements of the classic deep-V hull with its deadrise and lift strakes carried right back to the transom. Where the typical powered cat hull has been designed to offer minimal resistance in passing through the water, the Kiley hull is a true planing version that "gets up on the step".
"We've been producing high-end planing boats up to 27 feet for years," says third generation builder Dave Wright, who currently runs the family business with his uncle Ron, "We wanted to build a production 32-footer and we wanted something unique. When an Alaskan fishing guide that has several of our boats told us about this design out on the east coast that combined the soft ride of a deep-V with the roominess of a catamaran, we went to take a look."
After riding a 33-foot one-off prototype, the Wrights were impressed enough to go down to Florida and ride the first production model, a Benchmark 36, in 18 foot seas. "When we came back in over the bar, we dropped down in a hole right in front of the breakwater," enthuses Dave, "The operator just turned that boat across the face of the wave and powered back out of there. In a conventional hull we would have been on the rocks."
The Florida boat combines a pair of 420-hp Cummins with shafts and props. The Wrights worked with Seattle-based Cummins Northwest rep Scott Graf to select a pair of 6-cylinder Cummins Marine B-series turbocharged and aftercooled 5.9-litre Diamond Performance Series engines rated at 370 hp each. The engines drive Hamilton Model 273 jets through a 1:1 Borg Warner gear that reverses to back-flush the jet. The aft hull bottom has been faired up to optimize water flow to the jets.
The relatively wide asymmetrical hulls on the boat create a tunnel between the hulls with a chine-beam/tunnel ratio of 6:1. Well forward, on the centerline, a small V-shaped nacelle is molded into the form to prevent slapping at slower speeds and to deflect spray downward and into the channel. At higher speeds, the tunnel, which Kiley has patented as a Kinetic Fluid Induction (K.F.I.) channel, is filled with a mix of air and water that accelerates between the hulls to counter the negative effects of frictional resistance within the channel. It also tends to dampen the fore and aft pitching motion by providing a relatively stable pressure centre within the channel. Combined with the asymmetrical hull forms with their deeper deadrise on the outside, the channel allows the catamaran to bank noticeably into a turn by generating greater lift on the outside planing surfaces.
The utilization of jet drives on the Wright Brother's Sea Sport boat, allows the engines to be mounted well aft and outside of the spacious cabin. Dave explains that they will be able to deliver subsequent boats with prop drives if the customer prefers by reversing the engine and employing a V-drive. While they are expecting speeds over 35 knots with a 15,000 pound boat, Cummins power options on the B-Series engines will allow a lower horsepower on the same foot print for reduced cost and speeds that will still be in the mid-twenty knot range.
The boat currently under construction will be doing sea trials in Puget Sound in September 1997. Potential owners should be prepared to pay around $225,000 for the speed and the luxury of a full double bed and ample cabin space. With all of its features Sea Sport is betting the 32'X12'8" boat will find the kind of loyal following that the family's boats have earned in the past.
Excellent drawings are available now and running shots will be available after sea trials.
For more information and drawings, contact:
Sea Sport Boats Ph: 360 733-3380
John C. Kiley Design Ph: 508 428-8449
Scott Graf Ph: 206 235-3400