Representing the best meld of the tested qualities—noise, amperage, and water volume—were these five pumps. In the back (with the attached tank) is the #1 pump, the Johnson Aqua Jet Uno 3.4. It will be too big for many boats, but it's a heck of a pump. The other four are, front row, left, the Flojet Sensor VSD; front row, right, Flojet’s Quad II; middle row, left, Shurflo’s Extreme Series Smart Sensor, and middle row, right, the Johnson Aqua Jet 5.0.

At the heart of freshwater systems aboard boats are 12V pumps. Sometimes they're 24V, but that generally means you have a boat big enough to have paid help to worry about mundane things like water. We'll stick to the 12V units here.

Big, small, cheap, or expensive, one common denominator of all of these pumps is that they make noise in the confines of the boat—enough noise to be annoying. There are no secrets when people are running water in the middle of the night, and if there's a leak in the system, it's on, off, on, off, on, off... You can go bonkers. …