S.F. High School Student Introduces New Environmentally Friendly Plug for FJs

Tennis balls being used as dinghy plugs have been a staple for most sailors for years, particularly in the FJs and 420s competing in both high school and college sailing. A local junior sailor is trying to change that through a high school project.

Gus Gossett, 16, is a junior at The Bay School of San Francisco and a skipper on the school’s sailing team. He first came up with the idea of working on a new plug design for FJs as a freshman, in the school’s “creative process” class, but then shelved the idea for two years before picking it up again as a junior and refining it. Gossett has now introduced a plug design that he calls “ProPlug.”

“Most CFJ sailors are familiar with the tennis ball,” Gossett tells Latitude. “It works … sort of. But it always bugged me that such a well-designed boat relied on something so sloppy to keep water out. The CFJ is such a well-designed boat. That’s why I’ve always had a problem with the tennis ball that comes stock from the factory on CFJs from Zim Sailing. It always felt like a temporary fix that nobody ever bothered to improve.”

Gossett’s plug has gone through multiple iterations, with his two stated primary aims being to produce a plug that is more environmentally friendly than a tennis ball, and unlike the tennis ball, is specifically designed for the FJ.

“I designed the first ProPlug using tinkercad.com,” Gossett continues. “It came out looking super-bulky and unattractive. It was a start, though. Now, after 50+ iterations, I finally have a ProPlug I feel confident enough to sell. The goal was simple: Make a plug that’s lighter, cleaner, and actually designed for the boat. Every ProPlug is made from 100% recycled ocean plastic. It’s a small product, but it represents a bigger commitment to keeping our waters clean. The ocean gives us everything as sailors. It didn’t make sense to create more plastic waste when we could turn trash into gear.”

Gossett describes the design of the ProPlug, relative to a tennis ball. “I engineered the ProPlug so it’s 73% lighter than a DRY tennis ball, let alone a wet one. I also noticed that the tennis ball actually dips below the bottom edge of the hull, creating a small amount of drag that prevents the hull from moving through the water seamlessly. I wanted to solve this problem with a fully flush fit that didn’t stick out from the back. Early versions didn’t always lock into place when pulled from inside the hull. To solve this, I redesigned the plug with a conical shape, and after multiple rounds of testing, ProPlugs now snap in with a single pull. Another hurdle was durability — the painted steel hooks on the bungee fittings would rust over time. I upgraded them to stainless steel, eliminating the issue.”

“I get it — tennis balls feel like the go-to solution,” Gossett admits.”They’re cheap, and on the surface, there’s nothing ‘wrong’ with them … if you’re OK with extra drag, added weight, the environmental cost, then sure, stick with it. I designed ProPlug for teams who want more: better hydrodynamics, more speed, a cleaner environmental footprint, and a sleeker look on the water. Every day, I’m working to get FJ fleets around the world to adopt ProPlugs. St. Francis Yacht Club just converted their fleet of FJs to ProPlugs. I am also seeking high school and college sailing teams that are interested in switching. I have been using social media to market the plugs. I have been making lighthearted content that connects with sailors like myself, and explains the environmental detriment that comes from using tennis-ball plugs and the advantages of ProPlug. You can find us on Instagram @proplug_usa.”