If you have a front radius curve, here is how to measure:
You will need two measuring units (measuring tape or yard sticks). Where the railing starts to curve at the side of the boat, measure straight out to the front. Where the railing starts to curve at the front of the boat, measure straight out to the side. Where the two measuring units meet at a 90 degree angle, this will give you the length for the radius for your railing (just like the two white line on the images below).
Note: All of our seats are universally designed, so we can try to offer seats that will work for all boats. That being said, there is not a universal radius seat. We offer 30" radius or 36" radius and can offer a fit for most boats, but not all boats.