Check black water pump or risk sinking

Gilbert Park shares lessons learned from a messy job that may have saved his boat during a French cruising holiday

- Gilbert Park

After a lovely week-long trip up the River Rance, I purposefully approached Port des Sablons, St Malo, on a hot, sunny day. I'd chosen this marina because its facilities included a black water pump-out station.

The tank aboard Let's Go, my Mitchell 28 Classique, had filled up while away and for some reason wouldn't empty. When I used the pump, I could hear the motor whirr, but nothing was happening.

I suspected either an air leak on the tank side or that the impeller had disintegrated.

The pump and tank were located under the cockpit hatch, that could be lifted out of the way exposing the set up. I had tried tightening the hoses with no result except for producing a water leak, seemingly from the tank to seacock hose.

Nothing else for it-but a trip to the fuel berth to fill up with diesel and empty the black water tank, plus a few good flushes.

New pump

I spoke with Lee Sanitation about the problem and decided not to buy a replacement impeller but a whole new pump. Jabsco does make a replacement macerator pump, but you need to be aware that it shouldn't run dry (even though modern ones have dry protection) for a long period. They also make a toilet waste diaphragm pump that can run dry, however, it doesn't chop up waste, toilet paper and the like. I know, from my motorhome experience, that motion breaks down the toilet waste anyway. So I plumped for the latter.