By Greg Alder
In a sport where participants are more accustomed to describing the
of a board under their feet, Benjamin Thompson's goal is to develop hard data about the interaction between a surfer, a board and the water it's being ridden on.
The project led him to sponsor four UCSD engineering undergraduates to build velocity sensors connected to a computer into the body of a surfboard.
Thompson, a Ph. D. student in structural engineering at UCSD, gave the four undergraduates their mission as part of their senior project at the Jacobs School of Engineering. He tasked them to find out how fast water was traveling across the bottom of a surfboard.
"The whole point of the project was to develop a data acquisition system," said Thompson.
So the team procured plastic velocity sensors which are the size of your pinky nail and bend easily. They register data according to how far they're being bent, thus gauging the speed of the water flow. Eight of these sensors were sunk at different angles into the bottom of the surfboard.
Wires from the velocity sensors were connected to a computer set into the deck of the board. The computer, protected inside a small plastic box, glows blue when turned on.
Dan Ferguson and Trevor Owen were the surfers on the engineering team, and they first rode the board at a break in Del Mar in June while the other members, Julia Tsai and Victor Correa watched the data stream into a laptop on the beach. Within the plastic box that held the computer was also a transmitter that shot the data to a receiver hooked up to the laptop.
Ferguson said he was surprised at how well the system worked. Very little data got lost in transmission. Still, the team had also installed a memory card within the computer's box to record the data.
The team took the experiment to WindanSea for one additional surf session in July. They videotaped the waves they surfed there also, so later they could correlate the video and the velocity data and check their speed at specific points on a wave.
Thompson said the data would be available in the next few months on the website
Such an experiment has never been done, at least according to Dan Ferguson's knowledge.
"It's a good platform to start from. More iterations will perfect the system."
Next, Benjamin Thompson would like to use it to gauge the flex a surfboard undergoes while it is being ridden, he said.