What about Van de Stadt ? Surely they were in the steel boat plan business at the same time as Colvin ? Other than that when did Roberts kick off ?
Yes, Van de Stadt was designing some of the best boats of that era, with methods decades ahead of Colvin. Unlike Colvin, he made advances in steel boatbuilding, by thinking outside the box, and not geting stuck in a technological time warp, as Colvin did. Dealing with European bureucrartic control freaks, he took a huge and brave step in treating steel as a different medium, taking full advantage of the material, radically diffetent from the imitation wooden boatbuilding methods which Colvin stuck dogmatically to.
Van de Stadt 's boats were much better and more advanced boats than anything Colvin ever designed.
Roberts has some well saiing designs, but they reflect a lack of experience in working in steel. He stated in his last book that he designs his skegs to fall of if they hit anything, another demonstration of lack of experience. They are better boats than Colvins, shape wise, but you had better do some reinforcing of his skegs , and forget about this Spray design, a true disaster in steel.