Hi, Donald. I used to have a Com-Pac brand Sun Cat sailboat and when it came time to replace my scuppers, I sought advice from the Com-Pac owners group (CBrats for Com-Pacs). The consensus was that ping pong ones worked great-- the water coming up from the back pushed them closed and kept them closed-- unless you tried to sleep on the boat, which many owners did. Then, with weight in the cabin up front, the scuppers in the rear were not at-waterline or slightly submerged, and so the gentle waves lapping up and against them made the balls touch/close, then open, touch/close, then open, -- tap tap tap all night long-- to the point a few described eagerly ripping them out. So, I never bothered because I didnt need the tell tale heart on my boat, ha.
These small flap scuppers are self-bailing for when the boat is at anchor, on a mooring, in a slip, etc.. My Duxbury Dory skiff had no scuppers, just a deck-mounted bilge pump (facing straight down) and I was one dead battery away from a sunken boat in a rainstorm when it was at the dock. The Sun Cat never had water in it as it would drain behind via the flap scuppers, but the dory always had 2" or so in the corner below the pump's float switch (you dont want too low a switch or youll run your battery out faster)-- so most times using it began with a big orange sponge. (And the Picnic Cat, which I owned before, was so light the scuppers would be under water with more than 1 person in it, so us owners would plug them from the inside to keep our feet dry). Similar reporting on the Rosborough RF-246 earlier models, the 1990s and the later low-sided ones. Scuppers were raised later to prevent wet feet, as the eventual use became heavy laden cruising and the design needed to accommodate.
So, be happy you don't need a bilge pump and battery voltmeter, and can take vacations with your boat in the water without really worrying about it, but yeah, I'm of the mind "the best bailer is a scared sailor and a bucket". Even when you get into the Gallons Per Hour of some heavy duty bilge pumps, do the napkin math of volume of a cube and the back of the boat, and you'll realize you're never gonna get there. All boats like these are one good stern pooping away from being a newspaper article. All the more reason to keep the motor weight light so these things lift up closer to their design heritage before the dory stern was chopped for outboards. That's also why I like the line, "it's better to be in, wishing you were out, than out, wishing you were in!"
But I'm all for the necessity is the mother of invention, and applaud anyone using their brain to build a better mousetrap.
