Greetings and welcome aboard the CF, gcsitts.
Originally Posted by GypsyHawk
A few considerations. The vent line should be as short and straight as possible. The transom has relatively little airflow. A vent pipe and outlet is more effective if it has plenty of diameter ie 1" and if possible 1 1/2".
You might also add a second vent line, to the other side of the boat
. This will improve ventilation, reducing odour in the tank.