A j-class yacht is a single-masted racing sailboat built to the specifications of nathanael herreshoff's universal rule. the j-class are considered the peak racers of the era when the universal rule determined eligibility in the america's cup .. He is asking about j class boats, not boats designed by rod johnstone and family. fyi: plans for most (johnstone) j boats have been available for model makers pretty much since the original j24. not to mention the j boats have never been built by j boats, they have always been sub-contracted to licensees.. Books of detailed plans from different j boat designers is a bit of trick. you may find some books that contain great photos of these boats and once you settle on the one you want to build, you can find most plans at mystic seaport.. J boat | oldsailro | flickr ...