Installing a plastic, cabin-mounted opening port can be simple if you follow a few basic steps and take advantage of some helpful hints. The following procedure is for a new installation in a flat, single-layer wall with a 3/8" or greater thickness.
Choose the location for the port and tape the outer trim ring to the outside of the cabin wall. Make sure there is adequate space for the installation between the deck and the cabin top on both the inside and outside cabin walls. Drill two pin holes near the top corners of the ring, insert pins in the holes and place the ring on the pins, finished side out.
Trace the inside of the ring on the wall with a pencil. Drill several small holes inside the traced area close to the pencil line to allow starting a sabre or key hole saw, and cut on the outside of the pencil line.
Place the window in the hole and inspect it from the outside to make sure there is at least a 1/8" gap around the port for sealant to account for thermal expansion. If the window is tight, use a file to enlarge the hole. To help keep the port centered, use kitchen matches or small pieces of electrical wire as spacers, but be sure they can be completely sealed over.
Also, the port's spigot, which is the collar that passes through the wall, should protrude about 1/4" past the outside of the wall so that the spigot will be flush with the trim ring. This provides proper water drainage.
Following the above installation steps will help accomplish several objectives. You save money and time on labor. You know how the job was done and what is involved if alterations are needed. And it's a great reason to get out and use your hands.
Editor's note: Matt Reed is the OEM sales and customer service manager for port manufacturer Beckson Marine, Inc. He has 16 years of experience in the marine industry, with 12 years prior to that working in marine research on Long Island Sound.