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I installed a sailrite pre fab bimini on my 80 H 27 last year. The smallist fit fine with a few fitting adjustments.I did nit have to cut the top, only the height of the frame. It comes in stainless or aluminum. I chose the stainless. If you have split back stays, you'll have to make two holes in the top through which the backstays can run. Easy to do if you first measure the triangular distance from the end of the boom vertically to each backstay. Then, disconnect the backstays, and install the bimini frame with cover on. Then mark the canvas by transferring the measurments from the end of the boom to indicate where the backstays will pass through. Use a single edge rasor tocut o small hole so the backstays can pass through. Using wipping thread, sew in a ring ofn 1/4" tubing with an inner diamiter of about 3 or 4 inches.fpr support then cover the tubes with leather for chaff protection. If you follow these instructions, it will take about 4 hours with 2 people. It worked great....good luck.