Neighbor with a Catalina 320 asked if I wanted to go for a sail so I said sure. A few minutes later he cancelled the trip. The water fill and diesel fills are right next to each other on this boat. He put about ten gallons of water in his diesel tank. Probably too much water to rely on the water separator fuel filter? We towed it to a service marina so they could suck out the now toxic waste, clean, and refill.