A spat between two South County families over marketing rights in a sport called tarp surfing may be shaping up as an endless bummer.

Neither side is backing down.

Robert Brady and his family in San Juan Capistrano developed and marketed tarp surfing in 2009-10 with a website, bluetarpsurfing.com, popularizing around the world the practice of riding a skateboard beneath the curl of a blue tarp being pulled over the rider’s head.

When Brady saw that Carrie Kropfl of San Clemente and her family were doing a Kickstarter campaign to bring to market a portable tarp surfing product, he advised her that he holds a patent and they should talk.

When she didn’t reply, Brady wrote back. A dispute has escalated. Both parties said their attorneys affirm they are right – Brady to defend a patent he paid a lot of money for and Kropfl asserting her product is an evolution of tarp surfing not covered by Brady’s patent. She is seeking her own patent.

It appeared at one point that the two parties might sit down and talk last weekend, but Kropfl issued a news release saying that continued negative statements by Brady made it pointless to meet at this time.

“Mr. Brady is free to pursue his business venture and Streetubez encourages him to do so, as long as that pursuit does not infringe on Streetubez’ rights,” she wrote.

Brady’s response: “This is too good of a day to participate in all the drama,” he said via e-mail. “Just go out, have fun and get tubed … that is what it’s about. Aloha from the whole Blue Tarp Surfing crew!”

He reaffirmed his defense of the patent.

Streetubez is marketing its product at. The site says it is “coming soon.” A Kickstarter drive raised $8,204 but fell short of its $50,000 goal, canceling the pledges. “We plan on moving forward with producing Streetubez, are currently determining our next steps and will keep you posted on our progress,” Kropfl said in an e-mail.

“Clearly people realize Streetubez is going to be a huge success,” she wrote. “Otherwise we wouldn’t be under attack!”

Earlier, Brady had said that Blue Tarp Surfing had tried all shapes and sizes including a small version similar to the Kropfls’. He contended it isn’t an evolutionary improvement, as it is a “very short tube” and its lack of a blue tarp flooring diminishes the tarp surfing feel of being enveloped inside a blue wave.

Kropfl said Streetubez has “evolved tarp surfing into an all-inclusive, kid-friendly technology that is easy to set up, fun, safe, durable and simple to store.”

Contact the writer: fswegles@ocregister.com or 949-492-5127