Wind-Assist Marine Demonstration for San Francisco Bay Ferry Districts: Prospects for Saving Diesel Fuel with Wind Power

This sailing vessel testing, data collection and analysis project examined the “real world” potential for a novel carbon-fiber “wingsail” technology to reduce fuel use in potential passenger ferryboat applications. In the study, a series of controlled tests were performed, accomplished by using a wingsail wind-assist technology developed by Wind+Wing Technologies. The project involved building a carbon fiber wingsail that was then mounted on a 42-foot (14-meter) trimaran test vessel. The test vessel was outfitted with a complete instrumentation package with data-recording capability. The vessel was then operated on the San Francisco Bay on a daily basis over a three-month period. Data from polar routes and actual ferry routes were captured, compiled, and used for statistical analysis. This was a real world test, with a fully capable vessel and actual winds and tidal currents. The test results were conclusive that for a test vessel traveling at seven knots through water, up to 25 to 40 percent of the fuel burned can be saved through the use of the wingsail, depending on wind speed, with a corresponding reduction in greenhouse gases, toxic and criteria pollutant emissions, and fuel costs. These estimated fuel efficiency gains at a speed through water of seven knots will not necessarily translate directly to those at actual ferryboat service speeds (at 17 or more knots) but may due to the inherent ability of larger boats to sail at higher speeds at optimal efficiency points. Additional exploration of this scaling effect by boat size is suggested for further investigation.