If you have a Sea Ray with this style air vents, you probable have broken or missing grill.  They look bad and are an invitation for birds nests and varments.  I make a 3D printed replacement grill that mounts over the existing duct and uses the same screws to mount.  You just cut out what’s left of the old vent grill and screw on the new covers.  All of the work is done from the outside of the boat. Priced each.  Typically require 4 pieces to complete the job.  Screws not included.