Petrus, you got a point there.
If you had the vent below the rubrail and the water was jetted up along the side of the boat to the vent , it would be possible for the water to gravity flow into the tank. That being the case the loop should be immediately after and above the vent.
In bobby's case all he has to do is push the loop higher and secure the vent hose above the vent.
His vent location wouldn't allow water to jet into the vent.
