OCTOBER 2018 • FOGHORN 23 FOGHORNFOCUS: MARINE PROPULSION marinegroupbw.com | leah@marinegroupbw.com | [619] 621-2220 Marine Group Boat Works is the finest California boatbuilder and repairer of steel and aluminum high-speed ferries, catamarans and passenger vessels up to 220 feet-long. Operating two shifts, six days per week for fast turnarounds and minimized vessel time out-of-service. WHENTIMEIS OFTHEESSENCE YOU’REIN YOU’REOUT By Frederic Boyadjian Reprinted with permission from Scania W ith its bold futuristic look, the Clémentine is unlike any other vessel. Designed and manufactured by French company AdvancedAerodynamic Vessels (A2V), this 25-seater passenger boat features two Scania 600 hp 13-litre engines, selected for their reliability and low weight. From the front, the Clémentine’s airplane wing silhouette is closed on either side, making it look like a catamaran. From blank page to reality, A2V’s naval architects and computational fluid dynamics specialists worked for nearly two years to develop the revo- lutionary shape that safely transfers the boat’s weight from water to air, almost like a flying boat. A prototype was completed in 2015 and looked like an airplane wing resting on the water. The trials of the prototype met all ex- pectations and the innovative boat was ready for the market. It works like this: underneath the outer structure, air is slowed from 40 to 10 knots, creating an overpres- sure, while above it the air circulation generates a depressurizing effect. This pulls the superstructure upwards and lifts the vessel higher in the water so that it glides over the surface, even at lower speeds. “We managed to optimize the air drag around the ship so that, just like a plane, it does not act as a brake but actually smooths its passage,” says Gianluca Guelfi, a naval engineer and A2V partner. The Clémentine’s revolutionary shape gives it a speed and fuel con- sumption that small workboats cannot match. That’s because those other boats’ operational speed is restricted by the exponential increase in fuel consump- tion in relation to speed. Oversized engines allow higher speeds, but at the expense of much higher fuel consump- tion and reduced payload, leading to an economically and environmen- tally unsustainable cost per passenger. PVA MEMBERS: Advertise in FOGHORN! Contact Bill Forslund at bill@philipspublishing.com or call 206-284-8285 www.foghornmagazine.com