[bigeasy1]

I used to leave the plugs in on my 23 Tsunami I/O but it was a PIA when we needed to run the washdown to get rid of the fish blood.You'd pull the plugs out,and have to stand forward with the hose so water can drain out,and then you'd have to race to the back to put the plugs back in before water would come in.

I ended up making a simple equal to the "Vortex" invention by Fellowship.
**I took some 3/4' copper tube and cut a couple pieces about 2-1/2" long.
**I then soldered some very thin fine brass rod in an X pattern on the inside of one end.
**Got some 9 mil Nitrile rubber gloves and cut the fingers and finger tips off them.
**I just slide a finger over the tube and use a sinle layer of electrical tape to hold it
**The nitrile acts like a duck bill and it naturally wants to close,and acts like a check valve in reverse.

It works perfectly,the X shape of the rod that I soldered in go's on the bottom and is just there to prevent the rubber nitrile finger from reversing itself and going up into the tube from the water pressure when not moving or at a very slow troll.
I also just took a pair of needle nose pliers and bent two tabs to the outside of the tubes so that when they're placed in the scupper openings,they don't fall thru into the water.
I've run these for eight or ten days of continuous trolling from morning to late afternoon with rarely a problem.
Maybe once or twice every other day I take the washdown hose and stick the nozzle into the opening and blast any slime or errant debris that finds its way into the opening.

The nitrile gloves work the best,I tried latex,and other types, but the latex doesnt last and thicker material doesn't close tight enough.