I have a patent on a gate frame for the fence industry, a company with a existing frame challenged it and lost due to significant differences in structure and design. I had seen there product but honestly did not borrow heavily on their design because I wanted a different approach to doing the same thing.

That said, some things are standard in order for it to still be a gate frame. Vertical sides and horizontal rails are a must but how you get there is the real deal.

To me, the rub is actually copying or using a set of plans or templates I did not purchase. Aren't all modern kayaks a copy with or without some variation? Not that I would want to but I guess I could take measurements from my Boreal Ellesmere and make a SOF or strip boat.

Would that be copyright infringement?