I added the cockpit scupper to my C22. I also purchased a 2" "Fernco" rubber cap for the top of the rubber hose that the swing keel cable goes thru. For those of you who don't know what a Fernco is, it's a rubber plumbing fitting, which goes over steel, plastic, or cast iron pipe, then is secured by means of a stainless steel clam which is tightened with a screwdriver of socket wrench.
I drilled a 1/4" hole thru the center of the cap, then I used a utility knife to cut from the center of the cap and thru one side of the Fernco so that I could slip the Fernco over the cable, then position it onto the top of the rubber hose. I then secured it in place with the clamp.
The main benefit of installing the Fernco is that I no longer get water backing up the tube when using reverse on my outboard motor. I discovered this by accident while raising the keel to back up in a shoal area. I could see the water coming in from the top of the tube.