Re: Air vent for water tank on cs30
On the 30 the tank vent runs up behind the cabinet in the head. It runs as high as the underside of the deck and then loops downward for 5 to 6 inches. if you overfill the tank it will dribble into the bilge. If you remove the cabinet you can see it quite easily, you also gain access to the tank fill tube. It is the perfect spot to install a vented loop for the head.
The midship vent on the port side is a CS make shift anti-siphon line. The other end of the line is connected at the engine thermostat housing. You will find at high engine revs you will see and feel hot water dribbling out of the vent.