This is part five of a 10-part series chronicling the R&D of a wave energy converter. Read parts one, two, three, and four.
Author Nick Raymond next to the foam buoy before the epoxy resin is applied.
Once the design for the wave energy converter had been finalized, the team decided to start with building the buoy. During all of the frantic redesigning and changes from the WEC 003 to 004, the one thing that never changed was the size of the buoy. For that reason, the purchase order for the special marine-grade foam had been placed much earlier than any other supplies, and so the eight 5-gallon buckets were already sitting in the student workshop waiting to be mixed.
Tasked with designing the massive float, I spent a great deal of effort trying to keep it simple and easy to build. The objective was to maximize buoyancy and durability while minimizing cost and fabrication time. Ultimately, I proposed to build a cylindrical, solid foam buoy 5 feet in diameter and coated with epoxy resin and yellow color additive. Had the buoy been designed to be hollow, that same 40 gallons of liquid foam could have made a much larger, more buoyant buoy for the same price. Alternatively, we could have built the same size buoy but used less foam and saved some cash by leaving the center hollow. Besides the costs associated with testing the WEC in the ocean, the foam was the single most expensive purchase for the entire project, costing more than $1,000 before shipping. read more…