Vents
I allways use a 4" intake 24hr in the forward hatch. Depending on the size of the main cabin or head hatch I use an exhaust 24hr 3 or 4" depending on the size of the hatch. The idea is to help the natural convection currents in your boat - take it in low and blow it out high. The Nicro 24hr fans are not high speed high volume meaning you won't get cool by just standing in front of one, but they keep the air moving. Add a couple of 12v Hella's for that. I described what I did on my c320 in a "Fans, Fans, Fans" posting yesterday.Stan