Exhaust vented loop Catalina 27

[jlenox]

I just picked up my replacement HX to install. My 1984 Catalina 27 did not previously have a vented loop in the raw water return line that feeds the exhaust. I am looking for input from other C27 owners who may have installed an aftermarket vent for the best location. I know that it should be 18" above waterline on all angles of heel and above the highest point in exhaust. I was considering running the line through the access port in the port side cockpit locker and attaching the vent above the batteries, as close to midship as possibel, then returning the line to the exhaust. Any input and or photos would be appreciated.