How to measure Swim Platforms
Mark the center line of the transom and then lay a straight edge horizontally across the transom, touching at the center line.
Measure the distance A and B and average the numbers of inches. This is the 'arc'. Be sure to measure A and B 3" in from the edge of the transom so that the platform will be shorter than the beam to allow for safety in tight docking areas. Records of many Transom Curves are on file.