Marinco Day/Night vent with battery

[Sandalo]

I would like to install this vent in a 2006 33 ft in an existing cut out which is located mid ship. The cut out can be used for a vent and comes from the factory this way. Will a larger access be required for the 4 3/4 inch vent. If not will the 3 inch model work?

Thanks

 

[sail sfbay]

3 inch will work, albeit the larger the cut out the more air flow it will pass since cross-sectional area is a major determinant of airflow. A 4” diameter cowl vent has almost twice the area of a similar 3” vent.

Is the photo on the right the base flange for the new or existing vent?

Just replaced my cowl vents and fortunately found ones to fit the existing 4 inch cut out and screw hole pattern.

 

[Hayden Watson]

If you need to go with a larger diameter hole in the deck the easy way to do it is to drill the correct size hole into a piece of plywood. Then mount the base flange to the plywood to get the correct hole locations. using those screw holes, screw the plywood to the deck so that the old hole is fully contained inside the hole in the plywood. Use the plywood as a bit holder for the hole saw to cut the deck.

 

[Sandalo]

The picture on the right has the new cowling on top of the existing vent. It looks like it might fit but it sounds like I'm gonna have to use the 3 inch instead. I would prefer not to have to cut any additional holes in the boat.

Thanks for the replies

 

[Hayden Watson]

You shouldn't need to drill a new hole, just enlarge the current one.