1. Measure Carefully
Tape out the length and width needed to cover the area you have in mind. Most pads are 6 to 8 inches tall. If in doubt, have the upholsterer climb aboard to measure for you. Don't skimp on foam. Insist on thick marine-grade foam. Where two coaming pads meet in a stern quarter, ask the shop to finish the ends at complementary angles (mitered, so to speak). Make sure that the shop uses a mildew- and UV-resistant sewing thread, like Gore Tenara, for durable seams.