I doubt you will find a "direct" replacement. I just replaced all the fixed trapezoidal windows on my boat and after removing the original ports it became clear that using slightly larger windows and re-cutting the openinings more precisely would be an improvement. I had Bomon fabricate the new windows to my measurements. If you have windows made you may find, as I did, that the radius on the corners may have to be larger, requiring at least a little enlarging of the openings. I am not that familiar with the Ericson 35, but I have seen several Ericsons with Lewmar replacements for those small windows.