Catalina 350 International Association

I have hull #185 & have had continual problems with the fresh water intake flooding the bowl when not in use. I rebuilt the pump assembly last year with all new parts. I cleaned the vented loop & finally last week I completely replaced the vented loop with a new "True Design" type. With all of this being said, if I leave the through-hull open for any length of time, whether sailing or not, the bowl fills with water. It is NOT chemically treated water back flowing from the holding tank but clear, fresh water. Has anyone else experienced this problem? I can't seem to resolve it & feel I have tried everything?

Thanks for any input!

Justin Lee
"Kneedeep" #185

Hi,
I had exactly the same problem. I replaced the anti-siphon valve which I bought at West Marine, Part number Forespar MF841, 903002, its just a little piece of plastic duck bill to let air in the hose and stop water from siphoning in. I had to replace several on my boat last year.
Jan hull #303

Yes, I know about the "duckbill" valve, I tried cleaning it, then replacing it & finally replacing the ENTIRE vented loop with a new one but it STILL leaks?

I to know the "thrill" of sitting on a bowl in the dark that is full to the top. A real eye opener!!!
My duck bill valve stuck and that was the result.
As I understand the water path:
Seacock to head water pump input
waterpump output to vented loop
vented loop to top of bowl water input

If you remove the valve in the vented loop, this should break the water path and therefore not fill the bowl.
Wait a few hours to isolate your problem.
the vent (duck bill) should be inserted into the fitting so the valve will open on suction (Bills pointing down) double check .
The vented loop should be in the original position (mounted high above the waterline)
Someone else might have additional ideas to help you solve this.
Hope you solve this and let us know if you discover something new.

Leigh Weiss Brisa #155