I made this cap to utilize a hole cut out by the previous owner to run my sonar and power cables through. I mounted my transducer inside the hull and shoot through the bottom of the kayak. It should also help minimize water getting into the hull. I also used a backing plate to give the screws a little more bite along with a good dose of marine grade silicone. When not in use, I can just twist the cap 180 degrees and keep any unwanted bugs out.