Skimming along the canal in complete silence under partially cloudy skies, the Delta Lloyd Solar Boat looks like the ideal way to explore the waterways and riverbanks. But this is no pleasure craft. The Delta Lloyd Solar Boat Team competes in the Frisian Solar Challenge, effectively ‘The World Cup’ for solar powered boats, which takes the purely-solar powered contenders along a 220-kilometre-long route through the Dutch province of Friesland, a path made famous by the ‘Frisian Eleven Cities’ ice-skating race.
You might think that the Solar Boat Race would be held in sun-drenched climes, but the Frisian Solar Challenge sets out to prove that you do not need to live in the tropics to be able to generate and apply solar power. Reputed to be the largest race for solar vessels in the world, the biennial event is open to universities teams and specialist companies alike, which come to compete from all over the world.
The Delta Lloyd Solar Boat Team is a student run project from the Technical University of Delft in the Netherlands. Successive generations of Delft’s students have competed in the event, which had its inaugural race in 2006. Teams change every two years and Delft and the Delta Lloyd Solar Boat Team have already notched up two victories in the Open class race – in 2006 and 2008.
Each team builds a new craft and for 2010, the task was to optimise the winning hull design from the 2008 boat, introduce hydrofoils to maximise efficiency and contribute a new propeller design. The 2010 team used a new power train, motor and controller, so there were some changes to the CAN bus system to be made. They also wanted to improve their competition strategy by understanding how the components within the boat were performing at different stages of the race. For example, to know how much energy is coming from the solar panel arrays, how much energy is left in the battery and how much energy is being used to propel the boat. Their goal was to make all this information available for both the skipper and the onshore team.
Explained Bart Meenks, a member of the 2010 engineering team: “To interface with the CAN bus during testing and whilst sailing with the on board computer, a good quality CAN bus interface hardware was required, so we contacted Kvaser.” Kvaser responded by donating a Leaf Light, which could be used to test new components, as well as a PCI104 CAN bus interface for the on-board computer. “As our motor was a prototype”, noted Meenks, “the CAN bus commands were a bit unclear. However, using the Leaf Light and the very handy LabVIEW drivers and VI’s that Kvaser supplies via its website, we were able to figure out all the commands, problems and variables and managed to get the motor to spin the same day it arrived! In addition, the CANking software proved very useful in finding a problem with our CAN bus cabling and monitoring of the bus during testing.”
For the on board computer, Kvaser’s compact and stackable PC104 form factor proved ideal for the team’s needs. Says Meenks: “Although this was our first practical experience working with CAN bus, the Kvaser hardware, software and useful information on their website made the task much easier.”
With the introduction of hydrofoils, the 2010 team managed to achieve a top speed of 36 km/h whilst using the same power as the 2008 boat, whose top speed was 24 km/h. “Unfortunately, the hydrofoil concept worked three days too late and so we only came in third,” said Meenks. However, they did manage to set a new race top speed and won the last leg of the race.
At present, the 2012 team is being put together, though support will also come from the 2010 team whose have by Meenks admission, “all got the solar boat bug!” Meanwhile, work hasn’t stopped as the 2010 contenders are working on a wireless telemetry system to relay data to the onshore team, as well as an automatic stabilising system which will be controlled by CAN bus. “We hope that by improving the boat’s stability, we can reach the 40km/h,” Meenks concludes.