July 2008, Vol. 20, No.7

Waterline

Waterline

Biodiesel Powers Race Boat Around the World

 Earthrace, a sleek powerboat running on 100% biodiesel, has been making its way around the world since late April. The 23.7-m (78-ft) tri-hull wave-piercer is attempting to set the record time for boat travel around the globe.

The current record for fastest boat trip around the world belongs to a U.K. boat, Cable & Wireless Adventurer, which in 1998 made the trip in less than 75 days. Earthrace captain Pete Bethune and his crew hope to complete the voyage in less than 65 days, according to the Earthrace Web site.

The crew also is committed to a larger goal. “The Earthrace project was created to promote the awareness and use of alternative fuels, such as biodiesel,” Bethune said. Win or lose, Earthrace will be taken on a 2-year promotional tour, with stops in 100 cities around the world as a way to continue raising awareness of alternative fuels. The crew will meet locals, talk about their experiences, and express the importance of incorporating renewable fuels into energy usage.

At a speed of 6 knots, Earthrace can travel 24,000 km — more than halfway around the world at the equator — on one 11,355-L (3000-gal) tank of biodiesel. At a speed of 25 knots, it can travel about 3700 km on one tank of fuel.

In addition to the boat running on sustainable fuel, the project itself is carbon-neutral. All activities that would have caused carbon dioxide emissions, such as transportation of the biofuel and travel undertaken by the ground crew, have been offset by the purchase of carbon credits from www.downwithcarbon.org, according to the Earthrace Web site.

The race began and will end in Sagunto, Spain. Since the race calls for the boat to pass through the Suez and Panama canals, Earthrace is traveling close to the equator. On its way around the world, it is making 12 refueling stops at various ports. Fuel, provided by SGC Energia (Portugal), has been shipped to each of the stops so it is ready at the dock when Earthrace arrives.

At press time, Earthrace was running ahead of the world record. For more information, see www.earthrace.net.



Crops Calling for More Efficient Irrigation

A new irrigation-control system enables farmers to receive a phone call when plants are thirsty, thereby reducing overwatering and excess runoff. The SmartCropTM system, developed by Accent Engineering Inc. (Lubbock, Texas) and based on research by the U.S. Agricultural Research Service (ARS), lets plants “speak up” when they need water.

The heart of the system is a biologically identified optimal thermal interactive console (BIOTIC) that uses infrared thermometers to take plant temperatures. Each plant species has a fairly narrow range of internal temperatures preferred for best growth, according to an ARS press release. When leaf temperatures rise above the upper limit of that temperature range for too long, the plant needs water to cool down. When the system’s battery-operated infrared thermometer detects this heat stress, a wireless signal relays the information to a computerized base station that can send data to personal computers and text messages to cell phones through a cell-phone modem.

ARS has been researching precision irrigation controls since the late 1980s. For those farms already using an effective irrigation system, the BIOTIC system optimizes timing of water application but does not necessarily reduce water use, because it is meant to help maximize crop yield, ARS plant physiologist James Mahan said. The system has reduced overwatering from subsurface drip irrigation because farmers could not see that they were overwatering their crops, he added. Mahan explained that the system also helps farmers determine how late in the season and how soon after rainfall to water crops.

While farmers need to make sure their crops get enough water to be productive, overwatering can harm crops and the environment by causing fungi buildup and disease, water runoff, and potential groundwater contamination, the press release says.

SmartCrop’s sensors continuously track leaf temperature, air temperature, and relative humidity to provide site-specific irrigation needs. Farmers can choose the time–temperature threshold that will trigger an alert from the system and can change it any time. The sensors are placed throughout irrigated fields, usually one sensor for every 16 to 24 ha (40 to 60 ac), with as many as 16 sensors per system.

At press time, about 24 SmartCrop systems had been installed. For more information, see smartcrop.net or www.ars.usda.gov.