without a self draining cockpit, one pump was not OK...one is none and two is one... BACKUP please

Didn’t want to put another hole in my hull. So, rather than sharing the main bilge pump’s thru-hull fitting (with check valves) I ran the smaller hose up through the engine well through the boot and over the transom. This would later come back to bite me in a tender part.
With the boat fully loaded with fuel, water, provisions and cooking gear, the hose end went below the waterline. When I used it to clear a small accumulation from the sump, it was just enough water to fill the hose and start a reverse siphon.
The situation was deciphered and dealt with but could have been much more serious.
Sometimes we think we’re helping…