A small ball in the hunt for drifting fishing nets

¨Before i began my project i had no idea of the size of the problem i wanted to tackle. Well, it´s actually enormous. Every year over 8 million tons of plastic ends up in our oceans. 46 percent of this consists of discarded fishing nets. These strangle or suffocate more than 650,000 creatures a year. And the nets can remain out of there for up to 600 years.¨

Oliver Greenwood recently graduated from the Industial Design Engineering (IDE) degree programme. For his graduation project he created the Sonar Sphere: a simple ball made of recycled nylon. He believes that this ball can help find the ´phantom´ fishing nets that haunt the ocean.


¨Fishing nets are designed to be strong and long-lasting. They don´t easily break down and decompose in the ocean. And even when they do decompose after 600 years or so, fish will eat the microplastics. Through the food chain, these microplastiscs eventually end up in our body.¨

Sonar technology

Oliver conducted comprehensive research to find out what method was best suited for tracking and retrieving the discarded nets. “GPS and radio don’t work underwater, but sonar does. And sonar technology is already being used by fishers.” The smooth shape of the Sonar Sphere reflects sonar signals in every direction. The round ball can be attached to the net with a carabiner hook. If the net is lost, the Sonar Sphere never runs the risk of discharging as it doesn’t use batteries or contain any electronics.

Making a difference

“Like almost every Industrial Design Engineering student at THUAS, I care deeply about the environment. There is a growing trend among students to design products that contribute to a better and cleaner world. I hope  that  my idea will contribute to reducing the plastics problem in our oceans. When you think in solutions, you can make a difference.”