Join Date: Sep 2008
Location: Victoria B.C. Canada
Thanked 109 Times in 100 Posts
Rep Power: 10
The vented loop is in the raw water injection line before it goes into the exhaust elbow, like the Yanmar diagram below. As it says an anti-siphon or vented loop. Some install a vented loop with a small hose from the top into the cockpit well as it will not clog. And a bit of water spitting out is a comforting thing to see.
Living aboard in Victoria Harbour