[Fr. Frank]

I don't have pics, but I used to use an automatic 800 gph pump (which I hung over the side with a line) to fill my small 20 gallon on-deck tank, (cut down from a 30 plastic drum) and I used an 1100 gph automatic bilge pump mounted 3/4 of the way up the inside to pump the water back overboard, without having to get the tank drain above the gunwale or mount the tank in the back. I kept it in front of the console of my Carolina Skiff.
The automatic pump overboard cycled off when I pulled it out of the water to move somewhere else, and the auto pump in the tank only cycles on when the water in the tank was nearly full. The hoses both ran down the side of the tank, across the deck, and then up and over the gunwale. The only problem was I didn't plan on a simple way to empty the tank, so I would just tip it over on the deck to empty completely. The hoses just stored inside when not in use. Total cost was under $100.