Recently purchased a vintage 1978 Catalina 30'. Head and galley sinks keep filling with water - will not drain. Searched for a closed seacock - none found. Ran a snake down the drain - no luck - maybe will try some Drano? Any other suggestions?
The head doesn't 'drain' which I think you know. Consequently, you are mixing two different issues.
As to the sink, don't use drano please. Remove the hose where it attaches to the seacock and open it to see if the valve is functioning properly. The amount of water coming in should flow at a high rate. If not, voila! You just isolated the cause - no water = bad valve. Lots of water = clogged hose.The water which enters won't sink your boat .
Re the head - what happens when you try pumping it in dry mode?
To what does the sink drain hose attach on the hull?Thenks Don -- It is the sink in the head that is not draining. Don't see any seacock leading to the sink drains.
Thanks for the cautionary info on DRANO -- what was I thinking!!the head sink drain on my ex-boat was t'd into the drain for the galley sink- and 1 thru-hull